[ONNX] Update black_listed_operators for opset 12 (#39414)
Summary:
Remove black_listed_operators for opset 12 as we now support these ops.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39414
Reviewed By: hl475
Differential Revision: D21915584
Pulled By: houseroad
fbshipit-source-id: 37ec7bdd2b5a845484535054026d6613d0921b7a
