Revert "[export] allow Dim(1,2) for export dynamic shapes (#121642)"
This reverts commit a8dcbf2749f2081f939621db2d38fd15ab7e34a3.
Reverted https://github.com/pytorch/pytorch/pull/121642 on behalf of https://github.com/facebook-github-bot due to Diff reverted internally ([comment](https://github.com/pytorch/pytorch/pull/121642#issuecomment-1996121710))
