Switch from VLA to folly::small_vector
Switch from VLA to folly::small_vector

Summary: Switch from VLA to folly::small_vector

Reviewed By: yfeldblum, ot

Differential Revision: D23391426

fbshipit-source-id: c6c61f3f0eef5b6e71ad3a639fcfdb4fa1b7268e

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