Migrate masked_scatter_ CPU to ATen (#49732)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/49541
Reference: https://github.com/pytorch/pytorch/issues/24507
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49732
Reviewed By: ejguan
Differential Revision: D25991438
Pulled By: ngimel
fbshipit-source-id: a43bd0bfe043d8e32a6cadbbf736a0eaa697e7ec
