Revert "[Compiled Autograd] Turn accumulate_grad into an op (#111271)"
This reverts commit 04b04c068659127a53d659c44b0dd75fa9fd5887.
Reverted https://github.com/pytorch/pytorch/pull/111271 on behalf of https://github.com/jeanschmidt due to Breaking internal CI ([comment](https://github.com/pytorch/pytorch/pull/111271#issuecomment-1768527932))