Test at many moments from spring 1967 (before the epoch) to summer
2046 (after 32-bit time_t's sign-wrap).
Change-Id: I3932cc1553a868b8815fda9a8dfc7644e4485704
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>