[clang] [NFC][clang] Fix CodeGenSYCL::unique_stable_name_windows_diff test (PR #146854)

[Mariya Podchishchaeva via cfe-commits]

Fznamznon wrote:

> I noticed there is a problem with __builtin_sycl_unique_stable_name and sycl_kernel_etnry_point attribute. If I add this wrapping of __builtin_sycl_unique_stable_name calls AND sycl_kernel_entry_point attribute, the strings disappear from the IR. They are in here https://godbolt.org/z/KnPffTMYq , they disappear in https://godbolt.org/z/6jdvYEhK7 . Makes sense to fix it first instead of merging this.

Ah, according to https://github.com/llvm/llvm-project/issues/146566#issuecomment-3036813047 that was just my ignorance. I corrected the test so it tests correct targets and should be passing with https://github.com/llvm/llvm-project/pull/140282/files too. @tahonermann @schittir , could you please review?

https://github.com/llvm/llvm-project/pull/146854