[clang] [llvm] [SYCL] Add offload wrapping for SYCL kind. (PR #147508)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> @jhuber6 I had a choice to put it the common `OffloadWrapper.{h,cpp}` area. But SYCL's offload wrapping looks very different from others and I decided not to mix them together. Hence, I was choosing between `llvm/Frontend/Offloading/SYCLOffloadWrapper.h` and `llvm/Frontend/SYCL/OffloadWrapper.h`. If putting it together in `llvm/Frontend/Offloading/OffloadWrapper.h` looks better to you then I don't object to that.

OpenMP and HIP don't look similar either but I figured it was easier to just put them all together because they're basically exporting the same interface.

https://github.com/llvm/llvm-project/pull/147508