allow inplace leaky_relu backward calc when slope == 0 (#37453)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37453
to fix (#37345)
Test Plan: Imported from OSS
Differential Revision: D21290911
Pulled By: glaringlee
fbshipit-source-id: 81677e9e195298bc1bde82b77c51f52d58aa5422
