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.

std::vector<OutputGroup> applicable_groups;
    CAmount nTotalLower = 0;
    Shuffle(groups.begin(), groups.end(), rng);
    for (const OutputGroup& group : groups) {
        if (group.GetSelectionAmount() == nTargetValue) {
            result.AddInput(group);
            return result;
        } else if (group.GetSelectionAmount() < nTargetValue + change_target) {
            applicable_groups.push_back(group);
            nTotalLower += group.GetSelectionAmount();
        } else if (!lowest_larger || group.GetSelectionAmount() < lowest_larger->GetSelectionAmount()) {
            lowest_larger = group;
        }
    }
    if (nTotalLower == nTargetValue) {
        for (const auto& group : applicable_groups) {
            result.AddInput(group);
        }
        return result;
    }
    if (nTotalLower < nTargetValue) {
        if (!lowest_larger) return std::nullopt;
        result.AddInput(*lowest_larger);
        return result;
    }
    /
    std::sort(applicable_groups.begin(), applicable_groups.end(), descending);
    std::vector<char> vfBest;
    CAmount nBest;
    ApproximateBestSubset(rng, applicable_groups, nTotalLower, nTargetValue, vfBest, nBest);