Use parameter instead of looking up count

Author: romainbrenguier

src/goto-symex/symex_goto.cpp

@@ -466,11 +466,11 @@ void goto_symext::phi_function(
         rhs=goto_state_rhs;
       else if(goto_state.guard.is_false())
         rhs=dest_state_rhs;
-      else if(goto_state.level2_current_count(l1_identifier) == 0)
+      else if(goto_count == 0)
       {
         rhs = dest_state_rhs;
       }
-      else if(dest_state.level2.current_count(l1_identifier) == 0)
+      else if(dest_count == 0)
       {
         rhs = goto_state_rhs;
       }