Remove mention of Q_ASSERT in comments

This will make it easier to check for stray Q_ASSERT's in the future.

Change-Id: I5ddafe1bf26819566460920deae8ff448008c93f
Task-number: QTBUG-17582
Reviewed-by: Rohan McGovern
(cherry picked from commit b2db13f245f09f1d14af64d2199284c78cbb5b6e)

tests/auto/qwidget/tst_qwidget.cpp

@@ -10422,7 +10422,7 @@ void tst_QWidget::taskQTBUG_7532_tabOrderWithFocusProxy()
     w.setFocusProxy(fp);
     QWidget::setTabOrder(&w, fp);
 
-    // No Q_ASSERT, then it's allright.
+    // In debug mode, no assertion failure means it's alright.
 }
 
 void tst_QWidget::movedAndResizedAttributes()