Revert D30417370: [nnc] Enable CPU fusion
Test Plan: revert-hammer
Differential Revision:
D30417370 (https://github.com/pytorch/pytorch/commit/b9fc656cf26d60127bd695e4e5a7d27622f2563d)
Original commit changeset: 84ce7a578a36
fbshipit-source-id: cd23774cdc3273fd72f8a05f1900eaf36f373e6b
