Refactor C++ API parity test mechanism and turn it on in CI again (#35190)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35190
The following are the main changes:
- The main logic of C++ API parity test mechanism is moved from `test/test_cpp_api_parity.py` to `test/cpp_api_parity/module_impl_check.py` and `test/cpp_api_parity/functional_impl_check.py`, so that there is a clear separation between module tests and functional tests, although they still share a lot of common utility functions which are all in `test/cpp_api_parity/utils.py`.
- Module init tests (i.e. testing whether C++ module accepts the same constructor options as the corresponding Python module) is removed and will be added again in the future.
- `cpp_constructor_args` / `cpp_options_args` / `cpp_function_call` are added as appropriate to all test params dict in `torch/testing/_internal/common_nn.py`, to indicate how to run C++ API parity test for this test params dict.
Test Plan: Imported from OSS
Differential Revision: D20588198
Pulled By: yf225
fbshipit-source-id: 11238c560c8247129584b9b49df73fff40c4d81d
