Remove alpha tests

src/python/grpcio/grpc/early_adopter/__init__.py

src/python/grpcio/grpc/framework/alpha/__init__.py

src/python/grpcio/grpc/framework/base/__init__.py

src/python/grpcio/grpc/framework/face/__init__.py

...rpcio_test/grpc_protoc_plugin/alpha_python_plugin_test.py

...thon/grpcio_test/grpc_protoc_plugin/python_plugin_test.py

...test/_adapter/_blocking_invocation_inline_service_test.py

...apter/_event_invocation_synchronous_event_service_test.py

src/python/grpcio_test/grpc_test/_adapter/_face_test_case.py

...ter/_future_invocation_asynchronous_event_service_test.py

src/python/grpcio_test/grpc_test/_adapter/_links_test.py

.../grpcio_test/grpc_test/_adapter/_lonely_rear_link_test.py

src/python/grpcio_test/grpc_test/_adapter/_test_links.py

src/python/grpcio_test/grpc_test/early_adopter/__init__.py

...pcio_test/grpc_test/early_adopter/implementations_test.py

src/python/grpcio_test/grpc_test/framework/base/__init__.py

...cio_test/grpc_test/framework/base/implementations_test.py

...cio_test/grpc_test/framework/base/interfaces_test_case.py

...python/grpcio_test/grpc_test/framework/face/_test_case.py

...framework/face/blocking_invocation_inline_service_test.py