Delete ubuntu 16, 18, 20 RBE toolchains (#2848)
diff --git a/rbe-configs/cpp_env/ubuntu1804.json b/rbe-configs/cpp_env/ubuntu1804.json
deleted file mode 100644
index 9e6eba9..0000000
--- a/rbe-configs/cpp_env/ubuntu1804.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "ABI_LIBC_VERSION": "glibc_2.19",
-  "ABI_VERSION": "gcc",
-  "BAZEL_COMPILER": "gcc",
-  "BAZEL_HOST_SYSTEM": "i686-unknown-linux-gnu",
-  "BAZEL_TARGET_CPU": "k8",
-  "BAZEL_TARGET_LIBC": "glibc_2.19",
-  "BAZEL_TARGET_SYSTEM": "x86_64-unknown-linux-gnu",
-  "CC": "gcc",
-  "CC_TOOLCHAIN_NAME": "linux_gnu_x86"
-}
diff --git a/rbe-configs/cpp_env/ubuntu2004.json b/rbe-configs/cpp_env/ubuntu2004.json
deleted file mode 100644
index 9e6eba9..0000000
--- a/rbe-configs/cpp_env/ubuntu2004.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "ABI_LIBC_VERSION": "glibc_2.19",
-  "ABI_VERSION": "gcc",
-  "BAZEL_COMPILER": "gcc",
-  "BAZEL_HOST_SYSTEM": "i686-unknown-linux-gnu",
-  "BAZEL_TARGET_CPU": "k8",
-  "BAZEL_TARGET_LIBC": "glibc_2.19",
-  "BAZEL_TARGET_SYSTEM": "x86_64-unknown-linux-gnu",
-  "CC": "gcc",
-  "CC_TOOLCHAIN_NAME": "linux_gnu_x86"
-}
diff --git a/rbe-configs/cpp_env/ubuntu1604.json b/rbe-configs/cpp_env/ubuntu2204.json
similarity index 100%
rename from rbe-configs/cpp_env/ubuntu1604.json
rename to rbe-configs/cpp_env/ubuntu2204.json
diff --git a/rbe-configs/data.py b/rbe-configs/data.py
index 9ab3b06..6d95d6c 100644
--- a/rbe-configs/data.py
+++ b/rbe-configs/data.py
@@ -8,7 +8,7 @@
       },
       {
           'toolchain_name': 'ubuntu2204',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
+          'cpp_env_json': 'cpp_env/ubuntu2204.json'
       }
     ]
   },
@@ -16,20 +16,8 @@
     "bazel_version": "9.0.0",
     "containers": [
       {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-        'toolchain_name': 'ubuntu2004-bazel-java11',
-        'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
           'toolchain_name': 'ubuntu2204',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
+          'cpp_env_json': 'cpp_env/ubuntu2204.json'
       }
     ]
   },
@@ -37,20 +25,8 @@
     "bazel_version": "8.0.1",
     "containers": [
       {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-        'toolchain_name': 'ubuntu2004-bazel-java11',
-        'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
           'toolchain_name': 'ubuntu2204',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
+          'cpp_env_json': 'cpp_env/ubuntu2204.json'
       }
     ]
   },
@@ -58,20 +34,8 @@
     "bazel_version": "7.0.2",
     "containers": [
       {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-        'toolchain_name': 'ubuntu2004-bazel-java11',
-        'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
           'toolchain_name': 'ubuntu2204',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
+          'cpp_env_json': 'cpp_env/ubuntu2204.json'
       }
     ]
   },
@@ -79,260 +43,12 @@
     "bazel_version": "6.3.2",
     "containers": [
       {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
           'toolchain_name': 'ubuntu2204-bazel-java17',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
+          'cpp_env_json': 'cpp_env/ubuntu2204.json'
       },
       {
           'toolchain_name': 'ubuntu2204-java17',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "5.2.0",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "5.1.0",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "5.0.0",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "4.2.2",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "4.2.1",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "4.2.0",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "4.1.0",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-    ]
-  },
-  {
-    "bazel_version": "4.0.0",
-    "containers": [
-      {
-          'toolchain_name': 'ubuntu1604-bazel-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1604-java8',
-          'cpp_env_json': 'cpp_env/ubuntu1604.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu1804-java11',
-          'cpp_env_json': 'cpp_env/ubuntu1804.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-bazel-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
-      },
-      {
-          'toolchain_name': 'ubuntu2004-java11',
-          'cpp_env_json': 'cpp_env/ubuntu2004.json'
+          'cpp_env_json': 'cpp_env/ubuntu2204.json'
       },
     ]
   },