Revert D28800692: [nnc] Enable CPU fusion inside Facebook, take 3
Test Plan: revert-hammer
Differential Revision:
D28800692 (https://github.com/pytorch/pytorch/commit/6e7dae9cecad51eb274764eb6ac1569d62c78520)
Original commit changeset: d791c3b2ccd7
fbshipit-source-id: 5042fecfbab59181572013bf39760bc716e86430
