addmultisigaddress creates an address respecting the setting, being unable to generate a specific type of address without also adding it to the wallet seems wrong.

I suppose in the future `addresstype` may be refactored to be wallet-specific, which would leave this non-wallet rpc call without an argument. Perhaps there should just be an optional parameter to set it.
{
    nIndex = -1;
    keypool.vchPubKey = CPubKey();
    {
        LOCK(cs_wallet);
        if (!IsLocked())
            TopUpKeyPool();
        bool fReturningInternal = IsHDEnabled() && CanSupportFeature(FEATURE_HD_SPLIT) && fRequestedInternal;
        bool use_split_keypool = set_pre_split_keypool.empty();
        std::set<int64_t>& setKeyPool = use_split_keypool ? (fReturningInternal ? setInternalKeyPool : setExternalKeyPool) : set_pre_split_keypool;
        
        if (setKeyPool.empty()) {
            return false;
        }
        WalletBatch batch(*database);
        auto it = setKeyPool.begin();
        nIndex = *it;
        setKeyPool.erase(it);
        if (!batch.ReadPool(nIndex, keypool)) {
            throw std::runtime_error(std::string(__func__) + ": read failed");
        }
        if (!HaveKey(keypool.vchPubKey.GetID())) {
            throw std::runtime_error(std::string(__func__) + ": unknown key in key pool");
        }
        
        if (use_split_keypool && keypool.fInternal != fReturningInternal) {
            throw std::runtime_error(std::string(__func__) + ": keypool entry misclassified");
        }
        if (!keypool.vchPubKey.IsValid()) {
            throw std::runtime_error(std::string(__func__) + ": keypool entry invalid");