[truetype] Don't duplicate size->twilight structure to be freed. * src/truetype/ttinterp.c (free_buffer_in_size): Don't duplicate FT_GlyphZoneRec size->twilight to be freed. If duplicated, FT_FREE() erases the duplicated pointers only and leave original pointers. They can cause the double-free crash when the burst errors occur in TrueType interpreter and free_buffer_in_size() is invoked repeatedly. See Savannah bug #31040 for detail.