Include the intrin header before using intrinsics on MSVC
Include the intrin header before using intrinsics on MSVC

Summary: The tests that would have caught this aren't currently in the CMake file, but this is needed before trying to use the intrinsics here.

Reviewed By: yfeldblum

Differential Revision: D9952025

fbshipit-source-id: 40c7034ef7e0877ccb95525fa09ab46a3526af0b

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