Summary:
Many of our diffs dont have sandcastle tests because we failed to load arcanist token file (loaded over the network)
this diff try for at least 5 seconds (once every 0.2 second) to load the file instead of failing the first time the file is not found
This will make it less probable that diffs are submitted without sandcastle tests
Test Plan: arc diff --preview
Reviewers: kradhakrishnan, gunnarku, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D63951
42ac9c5f1e