Merge pull request #11367 from ncteisen/faster-bm-diff

tools/jenkins/run_performance.sh

tools/profiling/microbenchmarks/README.md

tools/profiling/microbenchmarks/bm_diff.py

tools/profiling/microbenchmarks/bm_diff/README.md

tools/profiling/microbenchmarks/bm_diff/bm_build.py

tools/profiling/microbenchmarks/bm_diff/bm_constants.py

tools/profiling/microbenchmarks/bm_diff/bm_diff.py

tools/profiling/microbenchmarks/bm_diff/bm_main.py

tools/profiling/microbenchmarks/bm_diff/bm_run.py

tools/profiling/microbenchmarks/bm_diff/bm_speedup.py

tools/run_tests/run_microbenchmark.py