While regtesting with [bitcoin-spock](https://github.com/msgilligan/bitcoin-spock) I noticed at some point the transaction creation via `sendtoaddress -> CreateTransaction()` fails, because the created transaction is larger than `MAX_STANDARD_TX_SIZE`.

During the process a lot of raw transactions are created, which have smallish outputs and when then using `sendtoaddress`, it appears to attempt to create a transaction that spends too many of those dust-ish outputs.

The transaction to create does not have many outputs, but it looks like it's caused by the coin selection, which selects too many inputs. Testing was done with a 0.9 branch, but on the first glimpse I believe this issue is as well be present in 0.10. If this is a known issue, and if there is already a guard against this behavior, I'd be happy about a hint.

Sorry in advance, I do not have a test script to reproduce this issue in an isolated manner. A potential fix would probably require to adjust the coin selection, so that it selects a combination of coins, which, in addition to the size of the rest of the transaction, is still smaller than the limit.

{
    SelectionResult result(target_value, SelectionAlgorithm::SRD);
    /
    /
    /
    /
    target_value += CHANGE_LOWER;
    std::vector<size_t> indexes;
    indexes.resize(utxo_pool.size());
    std::iota(indexes.begin(), indexes.end(), 0);
    Shuffle(indexes.begin(), indexes.end(), rng);
    CAmount selected_eff_value = 0;
    for (const size_t i : indexes) {
        const OutputGroup& group = utxo_pool.at(i);
        Assume(group.GetSelectionAmount() > 0);
        selected_eff_value += group.GetSelectionAmount();
        result.AddInput(group);
        if (selected_eff_value >= target_value) {
            return result;
        }
    }
    return std::nullopt;
}
/** Find a subset of the OutputGroups that is at least as large as, but as close as possible to, the
 * target amount; solve subset sum.
 * param@[in]   groups          OutputGroups to choose from, sorted by value in descending order.
 * param@[in]   nTotalLower     Total (effective) value of the UTXOs in groups.