[clang] Reapply "[Clang] Fix dependent local class instantiation bugs" (PR #135914)

[Younan Zhang via cfe-commits]

zyn0217 wrote:

> We're not really set up to run the full Fuchsia CI with specific upstream patches, and it's a bit too flaky and expensive to be much good for that anyway. For now, it's better as post-submit than pre-submit, I'm afraid.
> 
> So long as this fixes the issue in the reproducer, and the LLVM tests pass, that should be good enough to go in IMO.

I tested the reproducer locally and it passed with this patch.

Now that the CI is green, I'll go ahead and merge it - post-commit reviews are welcome



https://github.com/llvm/llvm-project/pull/135914