serialization: validate sparse tensors after loading (#34059)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/33439
This introduces torch._sparse_coo_tensor_unsafe(...) and
torch._validate_sparse_coo_tensor_args(...)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34059
Differential Revision: D22161254
Pulled By: ezyang
fbshipit-source-id: 994efc9b0e30abbc23ddd7b2ec987e6ba08a8ef0
