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

[Andrew Ng via cfe-commits]

nga888 wrote:

> > However, this fix also causes a dllimport test to fail too, so perhaps that was the "failure" that I encountered, I just don't remember.
> 
> Was this about `@_ZdlPv` in `clang/test/CodeGenCXX/dllimport.cpp`? Using `getMostRecentDecl()` makes that dllimport, and I think that's correct and matching MinGW's behavior: https://godbolt.org/z/Mzo1zGsrj

OK, so this change in behaviour is desirable and matches MinGW? The odd thing is that this behaviour doesn't change on the `main` branch or at least not with the version of it that I tried on Friday.

> I think we should proceed with switching to `getMostRecentDecl()`. Either a new PR or continuing in this one works for me.

I think it might be easier and simpler to go with a new PR.


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