OpInfos for torch.{flatten, column_stack} (#67555)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/67555
Test Plan: Imported from OSS
Reviewed By: cpuhrsch
Differential Revision: D32650384
Pulled By: anjali411
fbshipit-source-id: 9ead83b378d0ece60569e1a0fc7d8849f89566b3
