Revert D31386275: Migrate THCState to ATen
Test Plan: revert-hammer
Differential Revision:
D31386275 (https://github.com/pytorch/pytorch/commit/a6774d6e1f3a88f931a3786b7c2617a74bdaa50e)
Original commit changeset: 5c1f1bbe8c3d
fbshipit-source-id: bea4e80fb0bdc57e8bb6a8ee781afd224adf4ed0
