Include Portability.h before using FOLLY_HAS_COROUTINES
Include Portability.h before using FOLLY_HAS_COROUTINES

Summary: [Folly][coro] Include `Portability.h` before using `FOLLY_HAS_COROUTINES`.

Reviewed By: Orvid

Differential Revision: D7315956

fbshipit-source-id: 65490ced2573652e346c54aca4e67350fe3579fe

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