OpInfo for Slice (#85554)
This is based on wconstab tests from #84680
Technically, slice is covered by the __getitem__ opinfo, but it is
easier to debug/test on a more narrow internal function that only
uses this functionality and not other advanced indexing stuff.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85554
Approved by: https://github.com/mruberry, https://github.com/wconstab
