Added foreach_zero_ API (#46215)
Summary:
Adding Added foreach_zero_(TensorList) API
Tested via unit tests
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46215
Reviewed By: zhangguanheng66
Differential Revision: D24262885
Pulled By: izdeby
fbshipit-source-id: 144c283dd00924083096d6d92eb9085cbd6097d3
