Avoid memory leak in tst_qquicklistview

Change-Id: I74733325cdd81aa304c2e55acb257b1dbdb1300d
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

tests/auto/quick/qquicklistview/tst_qquicklistview.cpp

@@ -72,6 +72,7 @@ class tst_QQuickListView : public QQmlDataTest
     Q_OBJECT
 public:
     tst_QQuickListView();
+    ~tst_QQuickListView() { delete touchDevice; }
 
 private slots:
     // WARNING: please add new tests to tst_qquicklistview2; this file is too slow to work with.