[ROCm] Enable AMP autocast tests on ROCm (#39616)
Summary:
Enables AMP autocast tests on ROCm.
ezyang jeffdaily
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39616
Differential Revision: D21924219
Pulled By: ezyang
fbshipit-source-id: f4df4ad32cd8fae8c4620cd8ab18b00d74fb46bd
