[ONNX] Fix bug in unfold symbolic (#50504) (#51515)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51515
Fix bug in unfold symbolic
Test Plan: Imported from OSS
Reviewed By: pbelevich
Differential Revision: D26203113
Pulled By: SplitInfinity
fbshipit-source-id: 3a1b0013624d918de762a88ac6de8c9cafa0f732
