QmlJS: Fix basic code model test.

Change-Id: If62153e9db56e65e10d008d49f0945d3ea77c4f4
Reviewed-on: http://codereview.qt.nokia.com/1502
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@nokia.com>
Reviewed-by: Bill King <bill.king@nokia.com>

src/libs/qmljs/qmljsmodelmanagerinterface.h

@@ -139,6 +139,9 @@ public:
 
     virtual LibraryInfo builtins(const Document::Ptr &doc) const = 0;
 
+    // Blocks until all parsing threads are done. Used for testing.
+    virtual void joinAllThreads() = 0;
+
 public slots:
     virtual void resetCodeModel() = 0;