fix:
…/hpp-core/tests/roadmap-1.cc:298:20:   required from here
/usr/include/c++/10.2.0/bits/stl_function.h:386:20: erreur: no match for « operator< » (operand types are
« const std::weak_ptr<hpp::core::ConnectedComponent> » and
« const std::weak_ptr<hpp::core::ConnectedComponent> »)
  386 |       { return __x < __y; }
      |                ~~~~^~~~~

We don't need any ordering here.

Plus it's faster.