[llvm] [offload][SYCL] Add SYCL Module splitting. (PR #131347)

[Maksim Sabianin via llvm-commits]

maksimsab wrote:

I've moved the functionality into `llvm/Frontend/SYCL/`. Now `Transforms` area is not involved in this patch.

https://github.com/llvm/llvm-project/pull/131347