CallAPIv2Tests testMetadata and testErrorDebugInformation failure

[dennycd]

See the following sample

• https://source.cloud.google.com/results/invocations/ef4b1ae9-e83f-4b75-8707-ed36be9de786/targets/github%2Fgrpc%2Frun_tests%2Fobjc_macos_opt_native%2Fios-test-unittests/tests
• • https://source.cloud.google.com/results/invocations/c4d9082e-0eb7-47e8-ae9d-5561d03cb8d2/targets/grpc%2Fcore%2Fmaster%2Fmacos%2Fgrpc_basictests_objc_ios/log

Wed Sep 15 21:00:52 PDT 2021 - Test Case '-[CallAPIv2Tests testMetadata]' started.
Wed Sep 15 21:01:01 PDT 2021 - /Volumes/BuildData/tmpfs/src/github/grpc/workspace_objc_macos_opt_native/src/objective-c/tests/UnitTests/APIv2Tests.m:205: error: -[CallAPIv2Tests testMetadata] : Asynchronous wait failed: Exceeded timeout of 8 seconds, with unfulfilled expectations: "RPC unauthorized.".
Wed Sep 15 21:01:01 PDT 2021 - Test Case '-[CallAPIv2Tests testMetadata]' failed (8.465 seconds).

In addition, testErrorDebugInformation raises NSInternalInconsistencyException as follows

Wed Sep 15 21:01:15 PDT 2021 - 2021-09-15 21:01:15.822864-0700 xctest[41458:80151] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Unable to report test assertion failure '((error.code) equal to (16)) failed: throwing "Unable to report test assertion failure '((error.code) equal to (16)) failed: ("14") is not equal to ("16") - Finished with unexpected error: Error Domain=io.grpc Code=14 "{"created":"@1631764875.804842000","description":"Error received from peer ipv6:[2607:f8b0:4002:c11::451]:443","file":"/Volumes/BuildData/tmpfs/src/github/grpc/workspace_objc_macos_opt_native/src/core/lib/surface/call.cc","file_line":1074,"grpc_message":"502:Bad Gateway","grpc_status":14}" UserInfo={io.grpc.HeadersKey={

Also looks like we have