Renaming the relu kernel and adding hypothesis tests (#20647)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20647
The initial assumption was that `qint8` would be unsigned. After introduction of `quint8` and `qint8`, some tests break.
Reviewed By: jerryzh168
Differential Revision: D15332106
fbshipit-source-id: 6ed18da428915aea918a363c5f38754a3c75d06b
