[truetype] Restore non-persistent CVT and storage. According to specifications, CVT and storage area may or may not be persistent after modifications by a glyf program. FreeType had always reset them, which was broken by the last commit. * src/truetype/ttinterp.c (TT_Load_Context): Set CVT and storage here. * src/truetype.ttobjs.c (tt_size_run_prep): Prioritize TT_Load_Context. (tt_size_init_bytecode): Allocate but not set CVT and storage area.