Revert "[compiled autograd] support custom ops backed by c++ autograd::Function (#120681)"
This reverts commit 05c256849b464deee16ccd70152fd54071c6c79c.
Reverted https://github.com/pytorch/pytorch/pull/120681 on behalf of https://github.com/izaitsevfb due to breaking internal builds, see D54617701 ([comment](https://github.com/pytorch/pytorch/pull/120681#issuecomment-1984214079))
