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.

{
    return m_subtract_fee_outputs ? m_value : effective_value;
}
CAmount GetSelectionWaste(const std::set<COutput>& inputs, CAmount change_cost, CAmount target, bool use_effective_value)
{
    /
    assert(!inputs.empty());
    /
    CAmount waste = 0;
    CAmount selected_effective_value = 0;
    for (const COutput& coin : inputs) {
        waste += coin.GetFee() - coin.long_term_fee;
        selected_effective_value += use_effective_value ? coin.GetEffectiveValue() : coin.txout.nValue;
    }
    if (change_cost) {
        /
        /
        assert(change_cost > 0);
        waste += change_cost;
    } else {
        /
        assert(selected_effective_value >= target);
        waste += selected_effective_value - target;
    }
    return waste;
}
CAmount GenerateChangeTarget(const CAmount payment_value, const CAmount change_fee, FastRandomContext& rng)