It's not clear to me if dropping support for this functionality was intentional.

Chain of events:

- #21689 removed test coverage due to a misunderstanding due, I believe, to this functionality being generally supported by all platforms except macOS which does not and returns a different format
- #21756 removed support and caused this regression
- #21690 restores the test coverage that would have caught this regression

Currently, neither the test coverage before #21689 nor the coverage restored by #21690 pass since the merge of #21756.

{
    switch (addr.m_net) {
    case NET_IPV4:
    case NET_IPV6:
        valid = true;
        assert(addr.m_addr.size() <= sizeof(netmask));
        memset(netmask, 0xFF, addr.m_addr.size());
        break;
    case NET_ONION:
    case NET_I2P:
    case NET_CJDNS:
        valid = true;
        break;
    case NET_INTERNAL:
    case NET_UNROUTABLE:
    case NET_MAX:
        return;
    }
    network = addr;
}
/**
 * @returns True if this subnet is valid, the specified address is valid, and
 *          the specified address belongs in this subnet.
 */
bool CSubNet::Match(const CNetAddr &addr) const