[Dynamo][Export] Mitigate legacy issue that aten op as export entrance function (#119528)
This is going to fix a legacy issue like:
```
torch._dynamo.export(torch.ops.aten.scaled_dot_product_attention, ...)(*inputs,)
```
This is not supported any more, now the top level ```torch.export``` only support ```nn.Module```, but there are still some tests using the internal APIs and caused the ```trace_rules.check``` assertion error. This PR is going to mitigate such cases.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119528
Approved by: https://github.com/ydwu4
