Make bazel build fully hermetic

We no longer reference @bazel_tools//third_party. All of our transitive
dependencies are now specified explicitly in our WORKSPACE file.

I also fixed the way that jar dependencies are exported, so we don't
break strict dependency checking.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=116421176

java/com/google/common/testing/BUILD

@@ -3,5 +3,6 @@ package(default_visibility = ["//visibility:public"])
 java_library(
     name = "testing",
     testonly = 1,
-    exports = ["@bazel_tools//third_party:guava-testlib"],
+    exports = ["@guava_testlib//jar"],
+    runtime_deps = ["@guava//jar"],
 )