bug#20628: 25.0.50; Incorrect line height for some fonts

[Eli Zaretskii]

> From: Oleh Krehel <ohwoeowho@gmail.com>
> Cc: clement.pitclaudel@live.com,  20628@debbugs.gnu.org
> Date: Sat, 30 May 2015 21:26:03 +0200
> 
> frame 2
> #2  try_window_reusing_current_matrix (w=w@entry=0x11d5eb0) at xdisp.c:17245
> 17245       init_to_row_start (&it, w, first_row_to_display);
> 
> p first_row_to_display->y
> $1 = 909
> 
> p yb
> $2 = <optimized out>
> 
> p window_text_bottom_y (w)
> $3 = 909

Thanks, this confirms my suspicions: we are writing beyond the
window's glyph matrix.  I will see what can be done about that.