[truetype] Quietly reject out-of-spec `hdmx` tables. The `hdmx` table is optional and can be safely rejected without an error if it does not follow specifications. The record size must be equal to the number of glyphs + 2 + 32-bit padding. * src/truetype/ttpload.c (tt_face_load_hdmx): Thoroughly check the record size and improve tracing.