Revert D31577488: Migrate THCState to ATen
Test Plan: revert-hammer
Differential Revision:
D31577488 (https://github.com/pytorch/pytorch/commit/65adf1dfa2905f9a8397a55b30c748e1707c848b)
Original commit changeset: 90604f30854f
fbshipit-source-id: 3d7e35b3d6ea94f2c999bcf821b33a9cf1db01ee
