[gobject] Remove hb_language_t workarounds for g-i shortcomings Using latest gobject-introspection, I don't seem to be having this problem anymore: https://bugzilla.gnome.org/show_bug.cgi?id=707656 Removing that kludge makes language_t behave more like the way I expect it in Python. Also fixes: https://github.com/behdad/harfbuzz/issues/91