Merge pull request #2765 from ctiller/the-test-be-sleepy

src/core/client_config/subchannel.c

src/core/transport/chttp2/internal.h

src/core/transport/chttp2/stream_lists.c

src/core/transport/chttp2/writing.c

src/core/transport/chttp2_transport.c

test/cpp/end2end/end2end_test.cc