[libcxx-commits] [libcxx] [libc++] Avoid double comparisons when uniquing flat_set/flat_map (PR #214118)

[A. Jiang via libcxx-commits]

https://github.com/frederick-vs-ja requested changes to this pull request.

I don't think this PR is using better strategy than #175087 currently at all.

https://github.com/llvm/llvm-project/pull/214118