C++: also refresh files not in the project when project changes.

System headers and other file which are not explicitly mentioned in the
project must be reparsed when the project changes.

Task-number: QTCREATORBUG-9056
Change-Id: I32f1206d241a078a4d9b15fac5813f365a1ba303
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cpptools/cpptoolsplugin.h

@@ -137,6 +137,7 @@ private slots:
 
     void test_modelmanager_paths();
     void test_modelmanager_framework_headers();
+    void test_modelmanager_refresh();
 
 private:
     void test_completion();