[libcxx-commits] [libcxx] [libc++][NFC] Centralize test for support of == and != in ranges (PR #78481)

[Will Hawkins via libcxx-commits]

hawkinsw wrote:

If everyone is okay with this (especially @var-const ), I am more than willing to Squash and Merge.

https://github.com/llvm/llvm-project/pull/78481