Revert "Lift jagged -> padded dense forward / backward kernels from fbgemm_gpu (pytorch#125946)"

This reverts commit e2f0818.

Reverted pytorch#125946 on behalf of https://github.com/clee2000 due to I think dr ci is wrong and the windows build failure is real https://hud.pytorch.org/pytorch/pytorch/commit/e2f081837f4276c1a6a37739bd28157f62004a06 https://github.com/pytorch/pytorch/actions/runs/9216826622/job/25357819877 ([comment](pytorch#125946 (comment)))

Author: pytorchmergebot

aten/src/ATen/native/native_functions.yaml

@@ -14636,16 +14636,6 @@
     NestedTensorCUDA: NestedTensor_to_padded_tensor_cuda
   autogen: to_padded_tensor.out
 
-- func: _jagged_to_padded_dense_forward(Tensor values, Tensor[] offsets, SymInt[] max_lengths, float padding_value=0.0) -> Tensor
-  variants: function
-  dispatch:
-    CUDA: _fbgemm_jagged_to_padded_dense_forward
-
-- func: _padded_dense_to_jagged_forward(Tensor dense, Tensor[] offsets, SymInt? total_L=None) -> Tensor
-  variants: function
-  dispatch:
-    CUDA: _fbgemm_dense_to_jagged_forward_symint
-
 - func: _nested_tensor_softmax_with_shape(Tensor self, Tensor query) -> Tensor
   dispatch:
     NestedTensorCPU: NestedTensor_softmax_dropout