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.

BOOST_CHECK_EQUAL(result24->GetSelectedValue(), amt);
                BOOST_CHECK_EQUAL(result24->GetInputSet().size(), 1U);
            }
        }
    }
    
    {
        available_coins.Clear();
        for (int i2 = 0; i2 < 100; i2++)
            add_coin(available_coins, *wallet, COIN);
        
        for (int i = 0; i < RUN_TESTS; i++) {
            
            
            const auto result25 = KnapsackSolver(GroupCoins(available_coins.All()), 50 * COIN, CENT);
            BOOST_CHECK(result25);
            const auto result26 = KnapsackSolver(GroupCoins(available_coins.All()), 50 * COIN, CENT);
            BOOST_CHECK(result26);
            BOOST_CHECK(!EqualResult(*result25, *result26));
            int fails = 0;
            for (int j = 0; j < RANDOM_REPEATS; j++)
            {
                
                
                
                
                const auto result27 = KnapsackSolver(GroupCoins(available_coins.All()), COIN, CENT);
                BOOST_CHECK(result27);
                const auto result28 = KnapsackSolver(GroupCoins(available_coins.All()), COIN, CENT);