update core generation to be partial, update maxres to use current model too

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/smt/theory_arith_core.h

@@ -938,7 +938,7 @@ namespace smt {
                     m_new_atoms.pop_back();
                     --i;
                 }
-            }
+            }            
             ptr_vector<atom> occs(m_var_occs[v]);
 
             std::sort(atoms.begin(), atoms.end(), compare_atoms());