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

[Pierre van Houtryve via llvm-commits]

https://github.com/Pierre-vh commented:

I think I'm lacking context here.
Why does this have to be in `lib/Transform` ? How many targets will use it?
I'm a bit concerned seeing what looks like target specific files added to `Transform`

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