tst_MacGui::nonModalOrder fails on macOS 10.11

/Users/qt/work/qt/qtbase/tests/auto/other/macgui/target_wrapper.sh  ./tst_macgui -o /Users/qt/work/testresults/tests/auto/other/macgui403223491,xml -o -,txt
********* Start testing of tst_MacGui *********
Config: Using QtTest library 5.9.0, Qt 5.9.0 (x86_64-little_endian-lp64 shared (dynamic) release build; by Clang 8.0.0 (clang-800.0.42.1) (Apple))
PASS   : tst_MacGui::initTestCase()
QWARN  : tst_MacGui::scrollbarPainting() this function is deprecated, use QScreen::grabWindow() instead. Defaulting to primary screen.
XFAIL  : tst_MacGui::scrollbarPainting() QTBUG-26371
   Loc: [tst_macgui.cpp(90)]
PASS   : tst_MacGui::scrollbarPainting()
PASS   : tst_MacGui::dummy()
SKIP   : tst_MacGui::splashScreenModality() QTBUG-35169
   Loc: [tst_macgui.cpp(132)]
XPASS  : tst_MacGui::nonModalOrder() QCOMPARE(primary.frontWidget, primary.secondaryWindow) returned TRUE unexpectedly.
   Loc: [tst_macgui.cpp(194)]
QWARN  : tst_MacGui::spinBoxArrowButtons() this function is deprecated, use QScreen::grabWindow() instead. Defaulting to primary screen.
XFAIL  : tst_MacGui::spinBoxArrowButtons() QTBUG-26372
   Loc: [tst_macgui.cpp(216)]
PASS   : tst_MacGui::spinBoxArrowButtons()
PASS   : tst_MacGui::cleanupTestCase()
Totals: 5 passed, 1 failed, 1 skipped, 0 blacklisted, 7376ms
********* Finished testing of tst_MacGui *********