Avoid potential extra copy in _lu_with_info_cuda (#22634)
Summary:
No need to `clone` if the expanded size matches original size.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/22634
Differential Revision: D16171091
Pulled By: ezyang
fbshipit-source-id: 3d8f116398f02952488e321c0ee0ff2868768a0c
