[clang] [Clang] Apply exclude_from_explicit_instantiation to dllimport/dllexport (PR #168171)

[Hans Wennborg via cfe-commits]

https://github.com/zmodem commented:

Thanks for bearing with me.

I still wish these tests could be less complex. The functionality change isn't that complicated, but the tests seem to have hundreds of checks that will be hard to maintain.

Can't we just have a couple of classes with explicit checks for the stuff that's changing with this patch?

https://github.com/llvm/llvm-project/pull/168171