Upmerge from 1.3.0 to master

Fix a bug where OP_CANCEL is completed prematurely

clang-format

Make sure we set deadline for the LB call even without a pick.

clang-format

Code clean-up in client_channel.

Improve cq_verifier error message when success does not match.

Update internal Linux CI jobs

As part of this, get the deadline from a channel arg instead of pick_args.

Interop fixes

Fix Error Refcount Bug

fix truncate bug in grpc_cli

Added a missing ref in httpcli.c. Also added a test to avoid
regression

Implement client-side load reporting for grpclb.

Fix cmake build on Windows on internal_ci

Internal CI: Add macos grpc_master job

Use run_tests_matrix.py for running internal_ci master tests

Reports GC stats in qps workers

Reintroduce a lambda capture as part of C++11-izing code

Better presentation of reports in internal CI

New version of grpclb end2end test

Remove unused import in grpcio_health_checking.

Fix imports in generated gRPC Python code.