bug#11464: 24.1.50; pos-visible-in-window-p returns a false positive with bidi text

[Eli Zaretskii]

> From: Ari Roponen <ari.roponen@gmail.com>
> Cc: mwd@cert.org,  11464@debbugs.gnu.org
> Date: Fri, 18 May 2012 14:47:23 +0300
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Very strange, for both 300 and 302.  These values seem to imply that
> > the screen line where we wind up spans pixel coordinates [285..302],
> > which means move_it_to didn't get to its goal coordinate 303.
> >
> > What are the values of it.max_ascent and it.max_descent in this case,
> > at the point where the move_it_to call on line 1287 returns?
> >
> 
> it.max_ascent = 14
> it.max_descent = 3

Thanks.  This is consistent with top_y and bottom_y, but leaves open
the question why move_it_to didn't advance one more line.  I will try
to reproduce this on my system before I bother you with more
questions.