fix test build
fix test build

Summary: Fixes the build. Race condition during land.

Reviewed By: lnicco

Differential Revision: D15236913

fbshipit-source-id: 24ed32bd4b848d6364b02b6bc7dd3d46e355b310

facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst