std::less{}(ptr1, ptr2) may differ from std::ranges::less(ptr1, ptr2)

[CaseyCarter]

Specializations of std::less et al. yield a strict total order that is consistent with the builtin operators when given pointers. std::ranges::less et al. observe an implementation-defined strict total ordering over pointer values. These strict total orderings are not required to be the same.

We should merge the subclauses that define the std and std::ranges comparison function objects and require them to use the same ordering.