Revert "add amp tests (#85434)"
This reverts commit c2f4bbe66918d167401ff5804c6b2d24fc6bda40.
Reverted https://github.com/pytorch/pytorch/pull/85434 on behalf of https://github.com/clee2000 due to broke rocm and slow tests on trunk https://hud.pytorch.org/pytorch/pytorch/commit/c2f4bbe66918d167401ff5804c6b2d24fc6bda40
