[ONNX] Update unsafe_chunk() method to support new version 13 of Split operator. (#51415) (#51524)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51524
* def unsafe_chunk() support and test in ops13.
* Use _unsqueeze_helper insteadof Unsqueeze operator
* Cast the splits into long.
* Change the test to a fixed dimension.
* Update test_pytorch_onnx_onnxruntime.py
* Disable test_loop_with_list for opset 13.
Test Plan: Imported from OSS
Reviewed By: pbelevich
Differential Revision: D26203123
Pulled By: SplitInfinity
fbshipit-source-id: b273aeff8339faa0e8e9f1fcfbf877d1b703209f
Co-authored-by: Negin Raoof <neginmr@utexas.edu>
