[clang] [NFC][clang] change remaining context-dependent type nodes to ContextualFoldingSet (PR #67751)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

Thanks for the review.

I think the change stands on itself, as we are avoiding storing one pointer per Type Node instance, for the cost of one extra pointer per ASTContext, which is negligible.

These type nodes we are changing here are old, at least as far back as 2008.
In 2010 this `ContextualFoldingSet` folding set was added in this commit: b9639aaed4ef98becf413b9d52680686f8f22ca1
To solve exactly this problem as you can see in the commit description.

But we never went back and updated the existing users. This patch does that.

https://github.com/llvm/llvm-project/pull/67751