[numpy] `torch.erfinv`: promote integer inputs to float (#49155)
Summary:
Reference: https://github.com/pytorch/pytorch/issues/42515
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49155
Reviewed By: ngimel
Differential Revision: D25664234
Pulled By: mruberry
fbshipit-source-id: 630fd1d334567d78c8130236a67dda0f5ec02560
