Back out "[pytorch][PR] [fix] torch.frac : Handle inf correctly"
Summary: Original commit changeset: 92c7309558ee
Test Plan: reverting D27566407 (https://github.com/pytorch/pytorch/commit/ece075195d49c25213c96b9d53fcf7077215f44a)
Differential Revision: D27618949
fbshipit-source-id: 7930251f4bc88e7991805d77a617a181d68a4880
