get rid of connectivity state watchers right after timeout

CMakeLists.txt

Makefile

build.yaml

grpc.def

include/grpc/grpc.h

src/core/ext/filters/client_channel/channel_connectivity.c

src/core/ext/filters/client_channel/client_channel.c

src/core/ext/filters/client_channel/client_channel.h

src/ruby/ext/grpc/rb_grpc_imports.generated.c

src/ruby/ext/grpc/rb_grpc_imports.generated.h

test/core/surface/concurrent_connectivity_test.c

test/core/surface/num_external_connectivity_watchers_test.c

test/core/surface/sequential_connectivity_test.c

tools/run_tests/generated/sources_and_headers.json

tools/run_tests/generated/tests.json

vsprojects/buildtests_c.sln

...hers_test/num_external_connectivity_watchers_test.vcxproj

...t/num_external_connectivity_watchers_test.vcxproj.filters