CppEditor/CppTools: Avoid triggering garbage collector on editor close in tests

Closing an editor might trigger a timer which leads to the invocation of
the garbage collector. This is unfavourable for the plugin tests since a
test function closing an editor might influence a subsequent test
function (e.g. files get removed from the global snapshot although they
were added shortly before).

Change-Id: Ia80c11f99e2437fe145dc2d983b21962539b5181
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cpptools/cppmodelmanager.h

@@ -152,6 +152,8 @@ public:
         return m_definedMacros;
     }
 
+    void enableGarbageCollector(bool enable);
+
     static QStringList timeStampModifiedFiles(const QList<Document::Ptr> documentsToCheck);
 
 signals: