[ONNX] Fix gather squeeze axis in constant folding (#63588) (#64379)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64379
* Fix gather squeeze axis in constant folding
* mypy
* fix indent
* address comments
Test Plan: Imported from OSS
Reviewed By: jansel
Differential Revision: D30919604
Pulled By: malfet
fbshipit-source-id: 90edb054491433a0da2fe82324ac7c12f1ef062b
