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.

size_t ancestors, descendants;
            wallet.chain().getTransactionAncestry(output.outpoint.hash, ancestors, descendants);
            
            OutputGroup group{coin_sel_params};
            group.Insert(output, ancestors, descendants, positive_only);
            
            if (positive_only && group.GetSelectionAmount() <= 0) continue;
            if (group.m_outputs.size() > 0 && group.EligibleForSpending(filter)) groups_out.push_back(group);
        }
        return groups_out;
    }
    
    
    
    
    
    
    std::map<CScript, std::vector<OutputGroup>> spk_to_groups_map;
    for (const auto& output : outputs) {
        
        if (!output.spendable) continue;
        size_t ancestors, descendants;
        wallet.chain().getTransactionAncestry(output.outpoint.hash, ancestors, descendants);
        CScript spk = output.txout.scriptPubKey;
        std::vector<OutputGroup>& groups = spk_to_groups_map[spk];
        if (groups.size() == 0) {
            
            groups.emplace_back(coin_sel_params);
        }