[libcxx-commits] [libcxx] [libc++] Make sure `flat_set::key_compare` handle `boolean-testable` correctly (PR #132622)

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https://github.com/huixie90 requested changes to this pull request.

I added test to your branch. However, I noticed that in your branch the `flat_multiset` is not implemented. Could you please rebase main, updated the source code for `flat_multiset` and probably add the test that is similar to the test that I added for `flat_set`?

https://github.com/llvm/llvm-project/pull/132622