DO NOT MERGE: [truetype] Group deallocation of DeltaSetIdxMap into own function
Preparation for exposing DeltaSetIdxMap and VarStore service functions as a service.
- src/truetype/ttgxvar.c (ft_var_done_delta_set_index_map, ft_done_blend): Add ft_var_done_delta_set_index_map() and use it in ft_done_blend().