Migrate prelu_cuda_backward from CUDA_tensor_apply4 to TensorIterator (#33997)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/33997
Test Plan: Imported from OSS
Differential Revision: D20196786
Pulled By: VitalyFedyunin
fbshipit-source-id: 5d54a9226bd7f369f582192842be2fcd384bc7af
