pytorch

8d647972 - Revert "Adding Backward Support for NestedTensors and FlashAttention (#97485)"

Revert "Adding Backward Support for NestedTensors and FlashAttention (#97485)" This reverts commit 28d69d52569c8d140e83a2411e6066c903b94b29. Reverted https://github.com/pytorch/pytorch/pull/97485 on behalf of https://github.com/huydhn due to Sorry for reverting you change, but one of the tests test_fused_kernels_nested_broadcasting_requires_grad_failure_cuda is failing on Windows CUDA https://hud.pytorch.org/pytorch/pytorch/commit/f7ba3e85e26927ab5296737186ec32ef06c69a69 ([comment](https://github.com/pytorch/pytorch/pull/97485#issuecomment-1743474468))