Revert D27857735: ns for fx: bug fix for shadowing fp16 emulation patterns
Test Plan: revert-hammer
Differential Revision:
D27857735 (https://github.com/pytorch/pytorch/commit/f35540be38884de5a9a01588be3af37788d0afcb)
Original commit changeset: 7c1a067f035a
fbshipit-source-id: 6816223975b2e7b1f395e8894d17e3358fdb50ed
