[clang] Match against all plugins when parsing microsoft attributes (PR #86426)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

This has enough to do with parsing that i think Aaron should take a look too.

Also, this needs a parser test, not just the plugin test.  The plugins/examples aren't built often enough, so this needs to be a full lit test.

https://github.com/llvm/llvm-project/pull/86426