[hb] Pass down BOT/EOT flags to HarfBuzz
[hb] Pass down BOT/EOT flags to HarfBuzz

kari-lentz/alpha-pango,danny-ku/pango,Distrotech/pango,Distrotech/pango,kari-lentz/alpha-pango,danny-ku/pango,Distrotech/pango,danny-ku/pango,kari-lentz/alpha-pango,kari-lentz/alpha-pango