[libcxx-commits] [libcxx] [libc++] Fix tests on musl. (PR #85085)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne approved this pull request.

We don't really support Musl officially, however these changes are IMO not too strongly tied to Musl so it makes sense. In particular, the `put_long_double.pass.cpp` changes are simply making the test more generic so I think it's an overall win.

LGTM with green CI.

https://github.com/llvm/llvm-project/pull/85085