add erf and erfc to fuser/autodiff
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/15139
Differential Revision: D13455690
Pulled By: soumith
fbshipit-source-id: b06e5f5d362869c2e5fa11a52f9450d77c30d4cb
Author
Natalia Gimelshein
