Add QEXPECT_FAIL for failing tst_qwdidget test on Windows ARM

tst_QWidget::render_windowOpacity
  - Fails constantly, therefore QEXPECT_FAIL better than blacklist

tst_QWidget::enterLeaveOnWindowShowHide(dialog)
  - Known flaky, but doesn't need blacklist as it passes when
    rerun is used, no need for actions.

Task-number: QTBUG-128371
Task-number: QTBUG-128372
Task-number: QTQAINFRA-6396
Change-Id: I806419996fedea22628eecf311e977c74066d748
Reviewed-by: Tero Heikkinen <tero.heikkinen@qt.io>
Reviewed-by: Dimitrios Apostolou <jimis@qt.io>
(cherry picked from commit 975b4c078036427d2bf7026f1ba50ad095d83172)
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@qt.io>

tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp

@@ -8501,6 +8501,9 @@ void tst_QWidget::render_windowOpacity()
     painter.setOpacity(opacity);
     child.render(&painter);
     painter.end();
+#if defined(Q_OS_WIN) && defined(Q_PROCESSOR_ARM_64)
+    QEXPECT_FAIL("", "QTBUG-128371", Abort);
+#endif
     QCOMPARE(result, expected);
     }