Enable Constant Folding for ONNX Opset 12 (#34823)
Summary:
Currently constant folding is only enabled for ONNX opset versions 9 to 11. This PR enables it for the new ONNX opset 12.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/34823
Reviewed By: hl475
Differential Revision: D20627629
Pulled By: houseroad
fbshipit-source-id: 7501d8ab8295751c0e9a02752d8908a35d8a0454
