Fixes possible infinite loop in QApplication::topLevelAt
Fixes possible infinite loop in QApplication::topLevelAt

KDE Bug: https://bugs.kde.org/show_bug.cgi?id=191759
Reviewed-by: Bradley T. Hughes

radekp/qt,RLovelett/qt,radekp/qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,KDE/qt,RLovelett/qt,KDE/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,RLovelett/qt,pruiz/wkhtmltopdf-qt,KDE/qt,radekp/qt,radekp/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,RLovelett/qt,RLovelett/qt,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,KDE/qt,KDE/qt,RLovelett/qt,KDE/qt,KDE/qt,RLovelett/qt,radekp/qt,RLovelett/qt,RLovelett/qt,KDE/qt,RLovelett/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk