bug#9324: 24.0.50; Movement past end of screen causes weird jump

[Eli Zaretskii <eliz@gnu.org>]

> From: Ivan Andrus <darthandrus@gmail.com>
> Date: Thu, 25 Aug 2011 22:11:37 +0200
> Cc: antoine.levitt@gmail.com,
>  9324@debbugs.gnu.org
> 
> Indeed and that is very important to reproducing this bug.  What is your frame size?  Actually when building with athena I couldn't get the frame big enough, so I changed the test case a little.  At the end of the day what seems important is that the first line showing be a continuation line.  Then executing the (forward-sexp) gives the buggy behavior.

I've managed to reproduce this.  Please note that most of the `progn'
in bug-example-3.el is just clutter and is not needed to see the
problem (that clutter is part of the reason why it took so long to see
the problem).  Frame dimensions, mode-line face, exactly how you
scroll and recenter -- all these are irrelevant.  All you need is
this:

  emacs -Q -l highlight-parentheses.el -l hl-sexp.el bug-example-3.el
  C-u 1 C-v
  M-x goto-line RET 24 RET
  M-x hl-sexp-mode RET
  M-x highlight-parentheses-mode RET
  C-M-f

After this, Emacs moves point to be centered in the window, instead of
scrolling the window to show point at the end of the buffer, after the
sexp it was supposed to move across as result of C-M-f.

I fixed this in revision 105577 on the trunk.