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.

{
        assert(fee.has_value());
        return fee.value();
    }
    CAmount GetEffectiveValue() const
    {
        assert(effective_value.has_value());
        return effective_value.value();
    }
    bool HasEffectiveValue() const { return effective_value.has_value(); }
};
struct CoinSelectionParams {
    
    FastRandomContext& rng_fast;
    
    size_t change_output_size = 0;
    
    size_t change_spend_size = 0;
    /** Mininmum change to target in Knapsack solver: select coins to cover the payment and
     * at least this value of change. */
    CAmount m_min_change_target{0};
    /** Minimum amount for creating a change output.
     * If change budget is smaller than min_change then we forgo creation of change output.
     */
    CAmount min_viable_change{0};
    
    CAmount m_change_fee{0};
    
    CAmount m_cost_of_change{0};