Use static constexpr WaitOptions in UnboundedQueue
Use static constexpr WaitOptions in UnboundedQueue

Summary: [Folly] Use `static constexpr WaitOptions` in `UnboundedQueue` to save one store-word-to-stack instruction in the inlined fast path with gcc.

Reviewed By: magedm

Differential Revision: D13187890

fbshipit-source-id: 79a4f4ba585ed8abaebef344081bd364144f6cf8

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