[clang] [clang] Avoid stack exhaustion in recursive `constexpr` calls (PR #201706)

[Shafik Yaghmour via cfe-commits]

https://github.com/shafik commented:

@AaronBallman @erichkeane do we really want stack exhaustion tests? 

Also this does not feel like it addresses the core problems as outlines by @zygoloid in https://github.com/llvm/llvm-project/issues/201418

I actually would not have accepted this PR if I had reviewed it, I don't think this is the correct fix.

https://github.com/llvm/llvm-project/pull/201706