Merge remote-tracking branch 'upstream/v1.2.x' into HEAD

BUILD

examples/csharp/helloworld-from-cli/global.json

src/core/lib/channel/message_size_filter.c

src/core/lib/iomgr/resolve_address_uv.c

src/csharp/Grpc.Auth/project.json

src/csharp/Grpc.Core.Testing/project.json

src/csharp/Grpc.HealthCheck/project.json

src/csharp/Grpc.Reflection/project.json

src/csharp/global.json

src/node/ext/call.cc

src/node/ext/call.h

src/node/ext/call_credentials.cc

src/node/ext/channel.cc

src/node/ext/node_grpc.cc

src/node/ext/server.cc

src/node/ext/server_uv.cc