add validation for the range case (#8410)

Fixes  #6840

@efifogel I did not use expensive assertion as you mentioned because it
is already done this way in intersection and symmetric_difference.

Boolean_set_operations_2/include/CGAL/Boolean_set_operations_2/Gps_on_surface_base_2.h

@@ -642,6 +642,7 @@ class Gps_on_surface_base_2
  unsigned int i = 1;
  for (InputIterator itr = begin; itr != end; ++itr, ++i)
  {
+ ValidationPolicy::is_valid((*itr), *m_traits);
  arr_vec[i].first = new Aos_2(m_traits);
  _insert(*itr, *(arr_vec[i].first));
  }
@@ -666,6 +667,7 @@ class Gps_on_surface_base_2
  unsigned int i = 1;
  for (InputIterator itr = begin; itr!=end; ++itr, ++i)
  {
+ ValidationPolicy::is_valid((*itr), *m_traits);
  arr_vec[i].first = new Aos_2(m_traits);
  _insert(*itr, *(arr_vec[i].first));
  }