Disable bazel_docker_sandboxing_test on Ubuntu 16.04.

Bazel CI is migrating from Docker to Podman, which isn't available for that version of Ubuntu.

RELNOTES: None.
PiperOrigin-RevId: 294671201
diff --git a/.bazelci/postsubmit.yml b/.bazelci/postsubmit.yml
index 1984e3a..2222bcd 100644
--- a/.bazelci/postsubmit.yml
+++ b/.bazelci/postsubmit.yml
@@ -71,6 +71,8 @@
       # Re-enable once fixed: https://github.com/bazelbuild/bazel/issues/8162
       - "-//src/java_tools/buildjar/..."
       - "-//src/java_tools/import_deps_checker/..."
+      # Bazel CI uses Podman, but it's not available on Ubuntu 16.04.
+      - "-//src/test/shell/bazel:bazel_docker_sandboxing_test"
     include_json_profile:
       - build
       - test
diff --git a/.bazelci/presubmit.yml b/.bazelci/presubmit.yml
index 3484dc6..555224f 100644
--- a/.bazelci/presubmit.yml
+++ b/.bazelci/presubmit.yml
@@ -70,6 +70,8 @@
       # Re-enable once fixed: https://github.com/bazelbuild/bazel/issues/8162
       - "-//src/java_tools/buildjar/..."
       - "-//src/java_tools/import_deps_checker/..."
+      # Bazel CI uses Podman, but it's not available on Ubuntu 16.04.
+      - "-//src/test/shell/bazel:bazel_docker_sandboxing_test"
   ubuntu1804:
     shards: 4
     shell_commands: