Forbid inplace modification of a saved tensor's pack_hook input (#62717)
Summary:
When using saved tensors hooks (especially default hooks),
if the user defines a `pack_hook` that modifies its input,
it can cause some surprising behavior.
The goal of this PR is to prevent future user headache by catching
inplace modifications of the input of `pack_hook` and raising an error if
applicable.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62717
Reviewed By: albanD
Differential Revision: D30255243
Pulled By: Varal7
fbshipit-source-id: 8d73f1e1b50b697a59a2849b5e21cf0aa7493b76
