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.

#include <addrdb.h>
#include <addrman.h>
#include <chainparams.h>
#include <clientversion.h>
#include <cstdint>
#include <net.h>
#include <netaddress.h>
#include <netbase.h>
#include <serialize.h>
#include <span.h>
#include <streams.h>
#include <test/util/setup_common.h>
#include <util/strencodings.h>
#include <util/string.h>
#include <util/system.h>
#include <version.h>
#include <boost/test/unit_test.hpp>
#include <algorithm>
#include <ios>
#include <memory>
#include <optional>
#include <string>
using namespace std::literals;
class CAddrManSerializationMock : public CAddrMan