Revert D24262885: [pytorch][PR] Added foreach_zero_ API
Test Plan: revert-hammer
Differential Revision:
D24262885 (https://github.com/pytorch/pytorch/commit/8e37dcb1f3f5806b96aea3ddff54faf7c0a165b9)
Original commit changeset: 144c283dd009
fbshipit-source-id: 451b202e23bc1fcb11b20d26c11d9a1329789d22
