[clang] [clang] Fix loss of `dllexport` for exported template specialization (PR #93302)

[Andrew Ng via cfe-commits]

nga888 wrote:

> Here, `dllimport` gets dropped from `s::f<true>()` for the same reason as in your test: the AST node which the call in `template_using_f()` refers to is missing the attribute. (Godbolt: https://godbolt.org/z/nnfET4r13)

I think the difference in this case, is that this behaviour is unlikely to cause a "real" issue. The import of a definition/specialization is already a bit of an anomaly, so dropping `dllimport` is probably reasonable.


https://github.com/llvm/llvm-project/pull/93302