Fix coroutine integration with Expected on GCC
Fix coroutine integration with Expected on GCC

Summary: The same logic that was gated for MSVC is applicable to GCC as well (note that it had to be fixed).

Reviewed By: yfeldblum

Differential Revision: D33799604

fbshipit-source-id: 34bd7159c0cc37b5d49d631f715339512bfc4ddd

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly