OpInfos for stft, istft, fftshift, ifftshift (#68198)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68198
This unearths some bugs in istft backward, so I've disabled
backward tests but it's fixed in the next PR in the stack.
cc mruberry peterbell10
Test Plan: Imported from OSS
Reviewed By: VitalyFedyunin
Differential Revision: D32467044
Pulled By: mruberry
fbshipit-source-id: 5cf49560cbeb0263a66aafb48ed1bcc8884b75f1
