Revert "Extend Inductor to support the third-party backend (#100706)" (#106652)
This reverts commit 05bd24bb3548105776cf73226927cbd0ed575c55.
It caused compilation time regression on torchbench, huggingface and dynamic models.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106652
Approved by: https://github.com/davidberard98, https://github.com/voznesenskym
