[Resending] [ONNX] Add eliminate_unused_items pass (#42743)
Summary:
This PR:
- Adds eliminate_unused_items pass that removes unused inputs and initializers.
- Fixes run_embed_params function so it doesn't export unnecessary parameters.
- Removes test_modifying_params in test_verify since it's no longer needed.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42743
Reviewed By: hl475
Differential Revision: D23058954
Pulled By: houseroad
fbshipit-source-id: cd1e81463285a0bf4e60766c8c87fc9a350d9c7e
