[ONNX] Enable scripting tests and update jit passes (#41413)
Summary:
This PR initiates the process of updating the torchsciprt backend interface used by ONNX exporter.
- Replace jit lower graph pass by freeze module pass
- Enable ScriptModule tests for ONNX operator tests (ORT backend) and model tests by default.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/41413
Reviewed By: VitalyFedyunin
Differential Revision: D22845258
Pulled By: bzinodev
fbshipit-source-id: d57fd4086f27bd0c3bf5f70af7fd0daa39a2814a
