Avoid allocation from the hugepage allocator alloc_hook.
Avoid allocation from the hugepage allocator alloc_hook.

Summary:
The alloc_hook is invoked on the malloc path. Therefore we should not
allocate on this path.

Reviewed By: yfeldblum

Differential Revision: D14605677

fbshipit-source-id: f95b9ff3e14f65781045d26ce59ec008c113ca81

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