The necessary QT_ENABLE_P0846_SEMANTICS_FOR is already provided by
qpoint.h) here. Add a test to confirm it works.
Amends 0e22001a3b.
[ChangeLog][QtGui][QVector2/3/4D] Fixed manual get<I>() calls
(Tuple Protocol) in C++17 mode.
Task-number: QTBUG-111598
Change-Id: Id4a118b6439c2d1471b921f8d92ee558f9902eab
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>