[Bug libstdc++/113159] More robust std::sort for silly comparator functions

[ygribov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113159

--- Comment #14 from Yury Gribov <ygribov at gcc dot gnu.org> ---
(In reply to Xi Ruoyao from comment #12)
> Also note even
> 
> bool cmp(Element a, Element b) { return false; }
> 
> is a *valid* comparator, per the standard.

Hm, doesn't it violate the asymmetry axiom (cmp(x, y) => !cmp(y, x)) ?