Merge remote-tracking branch 'upstream/master' into cares_csharp

build.yaml

doc/health-checking.md

examples/php/route_guide/README.md

include/grpc/grpc.h

src/core/ext/lb_policy/grpclb/grpclb.c

src/core/ext/transport/chttp2/transport/chttp2_transport.c

src/core/lib/iomgr/tcp_server_posix.c

src/core/lib/surface/channel.h

tools/run_tests/run_tests.py

tools/run_tests/sources_and_headers.json