[clang] [clang][SYCL] Add SYCL spelling for AS attributes (PR #200849)

[Mariya Podchishchaeva via cfe-commits]

https://github.com/Fznamznon commented:

Thanks @elizabethandrews , I wonder if we should touch opencl_global_device/opencl_global_host at all since these will be removed anyway.

https://github.com/llvm/llvm-project/pull/200849