[libcxx-commits] [libcxx] [libc++][test] Fix simple warnings (PR #74186)

[Stephan T. Lavavej via libcxx-commits]

StephanTLavavej wrote:

@ldionne I've introduced a new macro for testing `constexpr`-in-C++23 code that avoids the need for complicated conditionals.

https://github.com/llvm/llvm-project/pull/74186