Disable RBE pre- and postsubmit due to breakage.

Due to a broken version check in bazel-toolchains, all Bazel versions starting from 4.1.0 fail to build with it and this error message is printed:

ERROR: Traceback (most recent call last):
	File "/var/lib/buildkite-agent/.cache/bazel/_bazel_buildkite-agent/ec321eb2cc2d0f8f91b676b6d4c66c29/external/rbe_ubuntu1604_java8/java/BUILD", line 19, column 60, in <toplevel>
		load("@bazel_tools//tools/jdk:local_java_repository.bzl", "local_java_runtime")
Error: file '@bazel_tools//tools/jdk:local_java_repository.bzl' does not contain symbol 'local_java_runtime'
ERROR: Analysis of target '//src:bazel_jdk_minimal' failed; build aborted: error loading package '@rbe_ubuntu1604_java8//java': Package 'java' contains errors

Bazel tracking issue #13502.

RELNOTES: None.
PiperOrigin-RevId: 375096580

.bazelci/postsubmit.yml

@@ -248,52 +248,6 @@ tasks:
     include_json_profile:
       - build
       - test
-  rbe_ubuntu1604:
-    shell_commands:
-      - sed -i.bak
-        -e 's/^# android_sdk_repository/android_sdk_repository/'
-        -e 's/^# android_ndk_repository/android_ndk_repository/' WORKSPACE
-      - rm -f WORKSPACE.bak
-    build_flags:
-      - "--config=ubuntu1604_java8"
-      - "--remote_executor=grpcs://remotebuildexecution.googleapis.com"
-      - "--jobs=200"
-      - "--experimental_remote_download_outputs=minimal"
-      - "--experimental_inmemory_jdeps_files"
-      - "--experimental_inmemory_dotd_files"
-    build_targets:
-      - "//src:bazel"
-      - "//src:bazel_jdk_minimal"
-    test_flags:
-      - "--config=ubuntu1604_java8"
-      - "--remote_executor=grpcs://remotebuildexecution.googleapis.com"
-      - "--jobs=200"
-      - "--experimental_remote_download_outputs=minimal"
-      - "--experimental_inmemory_jdeps_files"
-      - "--experimental_inmemory_dotd_files"
-    test_targets:
-      - "//scripts/..."
-      - "//src/java_tools/..."
-      - "//src/test/..."
-      - "//src/tools/execlog/..."
-      - "//src/tools/singlejar/..."
-      - "//src/tools/workspacelog/..."
-      - "//third_party/ijar/..."
-      - "//tools/aquery_differ/..."
-      - "//tools/python/..."
-      - "//tools/android/..."
-      # See https://github.com/bazelbuild/bazel/issues/8033
-      - "-//src/tools/singlejar:output_jar_simple_test"
-      - "-//src/test/shell/bazel:external_integration_test"
-      - "-//src/test/shell/bazel:bazel_repository_cache_test"
-      - "-//src/test/shell/integration:java_integration_test"
-      - "-//src/test/java/com/google/devtools/build/lib/sandbox/..."
-      # See https://github.com/bazelbuild/bazel/issues/8162 (also disabled for local exec)
-      - "-//src/java_tools/buildjar/..."
-      - "-//src/java_tools/import_deps_checker/..."
-    include_json_profile:
-      - build
-      - test
   kythe_ubuntu2004:
     shell_commands:
     - sed -i.bak -e 's/^# android_sdk_repository/android_sdk_repository/'

.bazelci/presubmit.yml

@@ -236,49 +236,6 @@ tasks:
       - "--test_env=TEST_REPOSITORY_HOME=$OUTPUT_BASE/external"
     test_targets:
       - "//src:all_windows_tests"
-  rbe_ubuntu1604:
-    shell_commands:
-      - sed -i.bak
-        -e 's/^# android_sdk_repository/android_sdk_repository/'
-        -e 's/^# android_ndk_repository/android_ndk_repository/' WORKSPACE
-      - rm -f WORKSPACE.bak
-    build_flags:
-      - "--config=ubuntu1604_java8"
-      - "--remote_executor=grpcs://remotebuildexecution.googleapis.com"
-      - "--jobs=200"
-      - "--experimental_remote_download_outputs=minimal"
-      - "--experimental_inmemory_jdeps_files"
-      - "--experimental_inmemory_dotd_files"
-    build_targets:
-      - "//src:bazel"
-      - "//src:bazel_jdk_minimal"
-    test_flags:
-      - "--config=ubuntu1604_java8"
-      - "--remote_executor=grpcs://remotebuildexecution.googleapis.com"
-      - "--jobs=200"
-      - "--experimental_remote_download_outputs=minimal"
-      - "--experimental_inmemory_jdeps_files"
-      - "--experimental_inmemory_dotd_files"
-    test_targets:
-      - "//scripts/..."
-      - "//src/java_tools/..."
-      - "//src/test/..."
-      - "//src/tools/execlog/..."
-      - "//src/tools/singlejar/..."
-      - "//src/tools/workspacelog/..."
-      - "//third_party/ijar/..."
-      - "//tools/aquery_differ/..."
-      - "//tools/python/..."
-      - "//tools/android/..."
-      # See https://github.com/bazelbuild/bazel/issues/8033
-      - "-//src/tools/singlejar:output_jar_simple_test"
-      - "-//src/test/shell/bazel:external_integration_test"
-      - "-//src/test/shell/bazel:bazel_repository_cache_test"
-      - "-//src/test/shell/integration:java_integration_test"
-      - "-//src/test/java/com/google/devtools/build/lib/sandbox/..."
-      # See https://github.com/bazelbuild/bazel/issues/8162 (also disabled for local exec)
-      - "-//src/java_tools/buildjar/..."
-      - "-//src/java_tools/import_deps_checker/..."
   kythe_ubuntu2004:
     shell_commands:
     - sed -i.bak -e 's/^# android_sdk_repository/android_sdk_repository/'