ONNX: support view_as operator (#40496)
Summary:
This PR adds support for the torch `view_as` operator.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40496
Reviewed By: hl475
Differential Revision: D22398318
Pulled By: houseroad
fbshipit-source-id: f92057f9067a201b707aa9b8fc4ad34643dd5fa3
