[libcxx-commits] [libcxx] [libc++][test] Migrate _BitInt probe to __BITINT_MAXWIDTH__ and fix latent test bugs (PR #203876)

[A. Jiang via libcxx-commits]

frederick-vs-ja wrote:

Thanks. Let's format `test_macros.h` later.

https://github.com/llvm/llvm-project/pull/203876