[clang] Using type deduction to define __SIZE_TYPE__ and __PTRDIFF_TYPE__ (PR #155979)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> @mizvekov The ast-dump test I added passes locally, but the CI is failing to match the string. How do I resolve this?

I would guess that kind of problem is due to line ending differences.

But in any case, I was thinking more about doing text-mode ast-dump tests.

If you want to do json only, that's fine as well, but then you could put them in `clang/test/AST/ast-dump-types-json.cpp`.

I don't think separate C and C++ tests are necessary, due to there not being any language mode differentiation on the implementation.

I would prefer for these tests to not depend on any external includes.

https://github.com/llvm/llvm-project/pull/155979