Use add_range instead an inner loop, clamp its input number by
number of glyphs a face has.
Even the face cmap12 and 13 have 32-bit hb_codepoint_t, which is here
used to make timeout, face's maxp has 16-bit gid limitation at least for now,
using that makes sure we both fix and the timeout and don't need to change
much things here also in order to support 32-bit gids also someday.
Fixes#2204
Michiharu Ariza
Ebrahim Byagowi