Summary:
Moves the `retry3` utility function into its own file so that it can be reused in other steps that are not related to Android.

Changelog:
[Internal]

Reviewed By: rickhanlonii, cipolleschi

Differential Revision: D39889996

fbshipit-source-id: bf79cc19ad6178af0a0d8117a81116e0c32f4333