Merge pull request #20401 from tanjunchen/clean-up

doc/interop-test-descriptions.md

examples/csharp/HelloworldXamarin/iOS/AppDelegate.cs

examples/python/cancellation/README.md

examples/python/cancellation/hash_name.proto

examples/python/data_transmission/README.en.md

src/compiler/ruby_generator_string-inl.h

test/cpp/util/cli_credentials.cc

test/cpp/util/proto_file_parser.h

tools/buildgen/plugins/check_attrs.py

tools/gce/linux_kokoro_performance_worker_init.sh

tools/github/pr_latency.py

tools/internal_ci/linux/grpc_publish_packages.sh

tools/interop_matrix/create_matrix_images.py

tools/interop_matrix/create_testcases.sh

tools/profiling/microbenchmarks/bm_diff/bm_main.py

tools/run_tests/performance/README.md

tools/run_tests/run_tests.py