Remove unnecessary call to [self descriptor] in resolveClassMethod:
Remove unnecessary call to [self descriptor] in resolveClassMethod:

This was causing problems in OCMock due to recursion when OCMock was trying
to mock a protobuf.

`_forwardStackInvocation:` was being called as part of the resolution of `descriptor`.

google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf