Add compatibility with CGAL_MESH_3_NEW_ROBUST_INTERSECTION_TRAITS

When CGAL_MESH_3_NEW_ROBUST_INTERSECTION_TRAITS is defined, the
Construct_intersection functor is always called, and Do_intersect_3 no
longer is. An assertion must be removed, because Construct_intersection can
be called on a query object that does not intersect the surface.

r66716 from Mesh_3-experimental-GF

Mesh_3/include/CGAL/Mesh_3/Labeled_mesh_domain_3.h

@@ -235,7 +235,9 @@ public:
 
     Intersection operator()(const Segment_3& s) const
     {
+#ifndef CGAL_MESH_3_NEW_ROBUST_INTERSECTION_TRAITS
       CGAL_precondition(r_domain_.do_intersect_surface_object()(s));
+#endif
       return this->operator()(s.source(),s.target());
     }