Fixed bug that didn't make strong updates in taint

Fixed bug that didn't make strong updates in
taint analysis when we had most-recent-allocation
dynamic-objects.

Author: mariusmc92

src/pointer-analysis/local_value_set_analysis.cpp

@@ -364,7 +364,12 @@ bool local_value_set_analysist::is_singular(const std::set<exprt> &values)
   if(values.size()!=1)
     return false;
 
-  const exprt &object=*values.begin();
+  exprt object=*values.begin();
+  if(object.id()==ID_member)
+  {
+    object=object.op0();
+  }
+
   if(object.id()==ID_dynamic_object)
   {
     return to_dynamic_object_expr(object).get_recency()==