Add SparsePrivateUse1 in backend_to_string, layout_from_backend and check_base_legacy_new. (#119263)
1) Using items stored in torch._tensor_classes to check item passed from python side;
2) Add SparsePrivateUse1 in backend_to_string, layout_from_backend and check_base_legacy_new;
3) Using more general API to get python module name in get_storage_obj and get_name functions.
Fixes #ISSUE_NUMBER
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119263
Approved by: https://github.com/ezyang
