bind-9.16: Correct reference counting
    
    With [0] BIND atomic functions for reference counting have the
    identical interface as their C11 counter parts. This means that
    these functions return the _previous_ refcount instead of the
    current one.
    
    [0]: https://gitlab.isc.org/isc-projects/bind9/-/commit/bef8ac5bae0f95dbff76ec99a7994024a5d6c64e