[libc++] Eliminate <compare>'s dependency on <array>.

This refactor is not only a good idea, but is in fact required by the standard,
in the sense that <array> is mandated to include <compare>.
So <compare> shouldn't have a circular dependency on <array>!

Differential Revision: https://reviews.llvm.org/D99307

GitOrigin-RevId: e21ab31f45a440e195f9c914083d57718e0de3b7
1 file changed