bug#29325: 26.0.90: Info scrolling stuck

[Eli Zaretskii]

> Date: Tue, 21 Nov 2017 21:42:59 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 29325@debbugs.gnu.org
> 
> > try_to_scroll looks like this:
> 
> I suspect we shouldn't go there in this case.  The logic above fails
> because it thinks we are at end of window, whereas we actually are at
> or before the beginning of window.

No, the last sentence is incorrect.  Nevertheless, something their
fails to work correctly because of how the various values involved
wind up, so I still want to see those values.