bug#39944: 27.0.90; JIT Stealth timer errors

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 06 Mar 2020 12:06:03 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > Date: Fri, 06 Mar 2020 12:01:46 +0200
> > From: Eli Zaretskii <eliz@gnu.org>
> > 
> > 
> > I see these errors in the 27.0.90 pretest from time to time:
> > 
> >   Error running timer ‘jit-lock-stealth-fontify’: (error "Invalid time format")
> 
> Additional information which is probably related: the *Message* buffer
> shows this from time to time:
> 
>   run-at-time: Invalid time format
>   ([nil 24162 5043 0 5 display-time-event-handler nil nil 0] [nil 24162 5046 46875 nil undo-auto--boundary-timer nil nil 0] [nil 24162 5098 187500 60 battery-update-handler nil nil 0] [nil 24162 54768 140625 86400 run-hooks (midnight-hook) nil 0])

This message comes from this fragment of run-at-time:

  (or (consp time)
      (error "Invalid time format"))

I guess this means the problem is general with timers, not specific to
JIT Stealth.