Summary:
The goal of this PR is to add an infrastructure; to convert(hipify) CUDA ops into [HIP](https://github.com/ROCm-Developer-Tools/HIP) ops , at **compile** time.
Note that HIP ops, which are portable c++ code, can run on AMD and NVIDIA platform.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/9322
Differential Revision: D8884707
Pulled By: bddppq
fbshipit-source-id: dabc6319546002c308c10528238e6684f7aef0f8