Set workspace name for http_file, http_jar, and maven_jar

Fixes #1166.

While I was here, I also:

* Renamed the implementations of Decompressor to show that they are
Decompressors, not SkyFunctions (they used to be, it's confusing to have them
still have the -Function suffix).
* Added a unit test and moved the testing target to the rule/repository
subdirectory, since it was a good chance to break off a tiny chunk of the
monolithic BUILD file in lib/.

--
MOS_MIGRATED_REVID=121306165
diff --git a/src/test/java/com/google/devtools/build/lib/BUILD b/src/test/java/com/google/devtools/build/lib/BUILD
index 3960aa7..7887b3b 100644
--- a/src/test/java/com/google/devtools/build/lib/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/BUILD
@@ -1,3 +1,7 @@
+package(
+    default_visibility = ["//src/test/java/com/google/devtools/build/lib:__subpackages__"],
+)
+
 # This should correspond to the list of "EMBEDDED_TOOLS" in TestConstants.java.bazel.
 filegroup(
     name = "embedded_scripts",
@@ -979,36 +983,6 @@
 )
 
 java_test(
-    name = "repository-rules-tests",
-    srcs = glob(["rules/repository/*.java"]),
-    tags = ["rules"],
-    test_class = "com.google.devtools.build.lib.AllTests",
-    deps = [
-        ":analysis_testutil",
-        ":testutil",
-        "//src/main/java/com/google/devtools/build/lib:bazel-main",
-        "//src/main/java/com/google/devtools/build/lib:build-base",
-        "//src/main/java/com/google/devtools/build/lib:cmdline",
-        "//src/main/java/com/google/devtools/build/lib:common",
-        "//src/main/java/com/google/devtools/build/lib:packages-internal",
-        "//src/main/java/com/google/devtools/build/lib:runtime",
-        "//src/main/java/com/google/devtools/build/lib:util",
-        "//src/main/java/com/google/devtools/build/lib:vfs",
-        "//src/main/java/com/google/devtools/build/lib/actions",
-        "//src/main/java/com/google/devtools/build/lib/rules/cpp",
-        "//src/main/java/com/google/devtools/build/skyframe",
-        "//src/test/java/com/google/devtools/build/lib:actions_testutil",
-        "//src/test/java/com/google/devtools/build/lib:packages_testutil",
-        "//third_party:guava",
-        "//third_party:jsr305",
-        "//third_party:junit4",
-        "//third_party:mockito",
-        "//third_party:truth",
-        "//third_party/protobuf",
-    ],
-)
-
-java_test(
     name = "bazel-rules-tests",
     srcs = glob([
         "bazel/rules/**/*.java",