Remove redundant ID_dynamic_object branch

This branch is not taken any more, at least in symex. The code in it
doesn't make much sense, which makes me think it isn't taken at all.

Author: Owen

src/pointer-analysis/value_set_dereference.cpp

@@ -291,24 +291,6 @@ value_set_dereferencet::valuet value_set_dereferencet::build_reference_to(
       result.ignore = true;
     }
   }
-  else if(root_object.id()==ID_dynamic_object)
-  {
-    // const dynamic_object_exprt &dynamic_object=
-    //  to_dynamic_object_expr(root_object);
-
-    // the object produced by malloc
-    exprt malloc_object=
-      ns.lookup(CPROVER_PREFIX "malloc_object").symbol_expr();
-
-    exprt is_malloc_object=same_object(pointer_expr, malloc_object);
-
-    // constraint that it actually is a dynamic object
-    // this is also our guard
-    result.pointer_guard = dynamic_object(pointer_expr);
-
-    // can't remove here, turn into *p
-    result.value=dereference_exprt(pointer_expr, dereference_type);
-  }
   else if(root_object.id()==ID_integer_address)
   {
     // This is stuff like *((char *)5).