Dynamo+LTC: add pybind to set force fallback config and use that in test_extract_compiled_graph.py (#75292)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75292
- Follow the convention in [this doc](https://docs.google.com/document/d/1Vi96ITGoK7BW01ZEccexs4pvCQKF4_LdV8w7TfIWPvM/edit) to setup config for ltc force fallback ops.
- Pybinds are added to read/set the config.
- Use the added pybinds in the unit test which needs to force fallbacks.
Test Plan:
```
pytest test/lazy/test_extract_compiled_graph.py
```
Reviewed By: malfet
Differential Revision: D35417678
Pulled By: shunting314
fbshipit-source-id: 1e05b8c831174872d70257a0ddd958863d6ca80d
(cherry picked from commit 9366bde7ef20837dcf03b7d8e18f9017a58c80fa)
