Change folly TSAN guard to only suppress read/write, not sync.
Change folly TSAN guard to only suppress read/write, not sync.

Reviewed By: igorsugak

Differential Revision: D26142316

fbshipit-source-id: 6ee85228e58f5068ee14154d02ad07f731c039ec

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