Remove redundant define.

Q_CHECK_PAINTEVENTS was guaranteed to be defined prior to the code that
was conditional on it being undefined.

Change-Id: I8b48a2c6bff997de7d0e3f640203308718dd865b
Reviewed-on: http://codereview.qt-project.org/6193
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>

tests/auto/qtabwidget/tst_qtabwidget.cpp

@@ -65,11 +65,6 @@
 # include <qwindowsystem_qws.h>
 #endif
 
-#ifndef Q_CHECK_PAINTEVENTS
-#define Q_CHECK_PAINTEVENTS
-#endif //Q_CHECK_PAINTEVENTS
-
-
 class QTabWidgetChild:public QTabWidget {
   public:
     QTabWidgetChild():tabCount(0) {