Gomory cut / branch and bound improvements

Improve fairness of cut generation by switching to find_infeasible_int_var with cascading priorities, allow stronger cuts by inlining terms.

src/smt/theory_lra.cpp

@@ -1678,7 +1678,6 @@ public:
                 return FC_CONTINUE;
             }
             
-
             for (expr* e : m_not_handled) {
                 if (!ctx().is_relevant(e))
                     continue;