Remove internal api canaries: they have never solved anything for us

CMakeLists.txt

Makefile

build.yaml

test/core/internal_api_canaries/iomgr.c

test/core/internal_api_canaries/support.c

test/core/internal_api_canaries/transport.c

tools/run_tests/generated/sources_and_headers.json

vsprojects/buildtests_c.sln

..._canary_iomgr_test/internal_api_canary_iomgr_test.vcxproj

...iomgr_test/internal_api_canary_iomgr_test.vcxproj.filters

...ary_support_test/internal_api_canary_support_test.vcxproj

...ort_test/internal_api_canary_support_test.vcxproj.filters

...transport_test/internal_api_canary_transport_test.vcxproj

...t_test/internal_api_canary_transport_test.vcxproj.filters