[ONNX] Remove the last Cast in pow symbolic_opset9 (#52646) (#53305)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53305
Fixes #52436
For opset 9 of onnx Pow, if X is int32, Y is float, we will cast back to int32 which is consistent with X type.
However, pytorch is still float. The aten graph sometimes does not bind with the type for operators,
we are fine with the float type and don't want to cast back.
Even if X, Y are int32, the resulting float32 and int32 makes no difference.
Test Plan: Imported from OSS
Reviewed By: pbelevich, malfet
Differential Revision: D26922425
Pulled By: SplitInfinity
fbshipit-source-id: f8c09524acee0de615df10a14310ca1dd583831e
