[WIP] Raise RuntimeError when models are missing get_module() implementation

[aaronenyeshi]

Since, we call get_module in each of the unit tests: train, eval, example, and check_device, the unit tests are skipped when get_module() is Not Implemented. This is because we catch NotImplemented in test.py. We should throw error when it is missing in any test.

[aaronenyeshi]

This change requires Issue #567 to be fixed.

[aaronenyeshi]

@xuzhao9 - I'm wondering if we should skip tests that don't have this implemented, so we can enforce this?

[aaronenyeshi]

Closing old prs