CppTools: Fix test_modelmanager_defines_per_project

Change-Id: Ia2e4dc776d3040d2ccb13d9b029c2f0cc8db0fcd
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cpptools/cppmodelmanager_test.cpp

@@ -775,7 +775,7 @@ struct EditorCloser {
     ~EditorCloser()
     {
         if (editor)
-            Core::EditorManager::closeEditors(QList<Core::IEditor*>() << editor);
+            Core::Tests::closeAndDeleteEditor(editor);
     }
 };
 }