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

[Daniil Dudkin via cfe-commits]

unterumarmung wrote:

@efriedma-quic added the test for `-fexperimental-new-constant-interpreter`. It passed, so I didn't change the actual code of the new interpreter. I also tested it with several `-fconstexpr-depth` values from 1024 to 128 and it passed all of them.

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