QtGui/Windows: Fix wait cursors remaining active

In QWindowPrivate::applyCursor(), do not apply override cursors
when the platform supports QPlatformCursor::OverrideCursor.

Complements b05d1c2ebf.

Task-number: QTBUG-65001
Change-Id: Ie84cc30ad99b22e037aae829a2ce847ec4bf900f
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

src/gui/kernel/qwindow.cpp

@@ -2790,6 +2790,8 @@ bool QWindowPrivate::applyCursor()
             if (!platformWindow)
                 return true;
             QCursor *c = QGuiApplication::overrideCursor();
+            if (c != nullptr && platformCursor->capabilities().testFlag(QPlatformCursor::OverrideCursor))
+                return true;
             if (!c && hasCursor)
                 c = &cursor;
             platformCursor->changeCursor(c, q);