Merge pull request #6090 from ctiller/perftest3

Makefile

build.yaml

src/proto/grpc/testing/control.proto

test/cpp/qps/gen_build_yaml.py

test/cpp/qps/json_run_localhost.cc

test/cpp/qps/qps_json_driver.cc

test/cpp/util/subprocess.cc

test/cpp/util/subprocess.h

tools/buildgen/generate_build_additions.sh

tools/run_tests/performance/build_performance.sh

tools/run_tests/performance/scenario_config.py

tools/run_tests/run_performance_tests.py

tools/run_tests/run_tests.py

tools/run_tests/sources_and_headers.json

tools/run_tests/tests.json

...cxproj/test/json_run_localhost/json_run_localhost.vcxproj

...est/json_run_localhost/json_run_localhost.vcxproj.filters

...ects/vcxproj/test/qps_json_driver/qps_json_driver.vcxproj

...proj/test/qps_json_driver/qps_json_driver.vcxproj.filters

vsprojects/vcxproj/test/qps_worker/qps_worker.vcxproj