Merge github.com:grpc/grpc into trim-the-locks

CMakeLists.txt

Makefile

build.yaml

test/cpp/microbenchmarks/bm_metadata.cc

test/cpp/microbenchmarks/bm_pollset.cc

tools/profiling/microbenchmarks/bm_json.py

tools/run_tests/artifacts/artifact_targets.py

tools/run_tests/artifacts/distribtest_targets.py

tools/run_tests/artifacts/package_targets.py

tools/run_tests/generated/sources_and_headers.json

tools/run_tests/generated/tests.json

tools/run_tests/performance/bq_upload_result.py

tools/run_tests/python_utils/antagonist.py

tools/run_tests/python_utils/filter_pull_request_tests.py

tools/run_tests/python_utils/port_server.py

tools/run_tests/python_utils/report_utils.py

tools/run_tests/run_build_statistics.py

tools/run_tests/run_interop_tests.py

tools/run_tests/run_microbenchmark.py

tools/run_tests/run_performance_tests.py