Type annotations in test/jit (#50293)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50293
Switching to type annotations for improved safety and import tracking.
Test Plan: Sandcastle tests
Reviewed By: xush6528
Differential Revision: D25853949
fbshipit-source-id: fb873587bb521a0a55021ee4d34d1b05ea8f000d
