Move fakelowp tests from glow to caffe2 (#36409)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36409
Pull Request resolved: https://github.com/pytorch/glow/pull/4409
Since glow OSS doesn't really ship with python, it's much easier to do it in pytorch. All the glow dependency can be done though LD_LIBRARY_PATH in OSS.
Test Plan:
```
buck test caffe2/caffe2/python/fakelowp:
```
Reviewed By: amylittleyang
Differential Revision: D20969308
fbshipit-source-id: 06a02d23f4972a92beb18e1d052e27d8724539d0
