[clang] [clang][modules] Fix std::initializer_list recognition if it's exported out of a module (PR #118537)

[Chuanqi Xu via cfe-commits]

https://github.com/ChuanqiXu9 commented:

The overall idea looks good. But the implementation may be improved. I didn't look at the implementation of std module in MSVC. But I am guess it is because the clang compiler failed to skip the transparent `export`  or `language linkage` context.

If yes, please attached a test and the release notes.

https://github.com/llvm/llvm-project/pull/118537