Move the OpInfo same-storage error to the autograd test (#88306)
This check was previously located at the `non_contiguous` test (quite
and odd location). Even more, at https://github.com/pytorch/pytorch/pull/86378#discussion_r993658395, Kshiteej found that this assert was not doing anything really.
We move it to the autograd test and make it a proper `self.assert`. We also disallow returning 1-tuples from sample_input functions, as they were breaking this assert.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88306
Approved by: https://github.com/mruberry
