[ONNX] Enable onnx shape inference in export by default (#46629)
Summary:
* Enable ONNX shape inference by default.
* ONNX could potentially set inferred shape in output instead of value_infos, checking both to be sure.
* Small fix in symbol_map to avoid overlooking dup symbols.
* Fix scalar_type_analysis to be consistent with PyTorch scalar type promotion logic.
* Correctly handle None dim_param from ONNX inferred shape.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46629
Reviewed By: ailzhang
Differential Revision: D24900171
Pulled By: bzinodev
fbshipit-source-id: 83d37fb9daf83a2c5969d8383e4c8aac986c35fb
