Merge pull request #1503 from ctiller/dont-signal-me

include/grpc/support/port_platform.h

src/core/iomgr/socket_utils_common_posix.c

src/core/iomgr/socket_utils_posix.h

src/core/iomgr/tcp_client_posix.c

src/core/iomgr/tcp_posix.c

src/core/iomgr/tcp_server_posix.c

test/core/util/test_config.c

test/cpp/qps/smoke_test.cc