8a375341cf added swap() to QJson* classes
and marked them shared-not-movable-until-qt6.
That unveiled a broken test in QVariant which was relying on QJsonDocument
being not relocatable. So fix the test by using a proper datatype for the task.
Change-Id: Ic35f09f936b00dfaeb368ccb42aecf35cc506029
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@qt.io>