supports non-leaf inputs for autograd.backward() function (#60521)
Summary:
Close https://github.com/pytorch/pytorch/issues/60268
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60521
Reviewed By: ngimel
Differential Revision: D29393586
Pulled By: albanD
fbshipit-source-id: 2dd2de427ecfecca8d544237bacf690e0b7c918c
