make custom op work in OSS environment (#22781)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/22781
The custom op is required to make the op benchmark work with JIT. Running this command `python setup.py install` in the pt_extension directory to install it. It is required.
Reviewed By: hl475
Differential Revision: D16214430
fbshipit-source-id: c9221c532011f9cf0d5453ac8535a6cde65e8376
