tst_qgraphicswidget fails on Ubuntu

 
  QtQA::App::TestRunner: begin tst_qgraphicswidget: [./tst_qgraphicswidget] [-silent] [-o] [/work/ci/qt/qt5/dev/_artifacts/test-logs/tst_qgraphicswidget-testresults-00.xml,xml] [-o] [-,txt]
  Testing tst_QGraphicsWidget
  FAIL!  : tst_QGraphicsWidget::initialShow2() 'QTest::qWaitForWindowActive(dummyView.data())' returned FALSE. ()
     Loc: [/work/build/qtbase/tests/auto/widgets/graphicsview/qgraphicswidget/tst_qgraphicswidget.cpp(3185)]
  Totals: 141 passed, 1 failed, 0 skipped, 0 blacklisted
  QtQA::App::TestRunner: test failed, running again to see if it is flaky...
  ********* Start testing of tst_QGraphicsWidget *********

  ********* Finished testing of tst_QGraphicsWidget *********
  QtQA::App::TestRunner: test failure could be reproduced twice consecutively
  QtQA::App::TestRunner: end tst_qgraphicswidget: 6 seconds, exit code 1
  QtQA::App::TestScheduler: tst_qgraphicswidget failed