Fix a backend test by using local backend (#19230)
The decomposition pass (e.g., converting torch.add to aten.add) in DORT
no longer exists. Therefore, we have to use `use_aot_autograd=True` to
enable Dynamo's built-in operator decomposition. I think we need to add
the decomposition pass back to DORT or remove `use_aot_autograd` (remove
because it will always be `true`).
