[coretext] Reverse glyphs if right-to-left
[coretext] Reverse glyphs if right-to-left

The shape.c layer is doing this for clumsy backends but warns.
Fix properly.

danny-ku/pango,danny-ku/pango,danny-ku/pango,Distrotech/pango,Distrotech/pango,Distrotech/pango