bug#39133: 28.0.50; Emacs slowdown on special char

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>,
>   39133@debbugs.gnu.org,  lg.zevlg@gmail.com,  handa@gnu.org
> Date: Fri, 24 Jan 2020 11:13:54 +0100
> 
> >>>>> On Wed, 15 Jan 2020 18:19:28 +0200, Eli Zaretskii <eliz@gnu.org> said:
>     Eli> We could do in the 'else' branch the same we do in the single caller
>     Eli> of this function, fill_gstring_body, when we don't call
>     Eli> font_fill_lglyph_metrics:
> 
> Rather than duplicate that code, I moved the FONT_INVALID_CODE check
> up. This works for me:

Looks reasonable, thanks.