Pull up following revision(s) (requested by nia in ticket #1124):

sys/kern/kern_time.c: revision 1.206

kern_time: prevent the system clock from being set too low or high
currently doing this will drive KUBSAN haywire and possibly cause
system lock-ups, so more testing should probably be performed before
we let the clock be set too many thousands of years into the future.

ditto for negative values, which were being passed by chrony for
some reason while my internet connection was being unreliable.
this also triggered some interesting KUBSAN reports.

(martin)