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.

{
    const int input_bytes = 148;
    const CFeeRate feerate(1000);
    const CAmount nValue = 10000;
    const int nInput = 0;
    CMutableTransaction tx;
    tx.vout.resize(1);
    tx.vout[nInput].nValue = nValue;
    
    COutput output1(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput),  1, input_bytes,  true,  true,  true,  0,  false, feerate);
    const CAmount expected_ev1 = 9852; 
    BOOST_CHECK_EQUAL(output1.GetEffectiveValue(), expected_ev1);
    
    COutput output2(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput),  1,  -1,  true,  true,  true,  0,  false, feerate);
    BOOST_CHECK_EQUAL(output2.GetEffectiveValue(), nValue); 
    
    COutput output3(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput),  1, input_bytes,  true,  true,  true,  0,  false, CFeeRate(100000));
    const CAmount expected_ev3 = -4800; 
    BOOST_CHECK_EQUAL(output3.GetEffectiveValue(), expected_ev3);
    
    const CAmount fees = 148;
    COutput output4(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput),  1, input_bytes,  true,  true,  true,  0,  false, fees);
    BOOST_CHECK_EQUAL(output4.GetEffectiveValue(), expected_ev1);
    
    COutput output5(COutPoint(tx.GetHash(), nInput), tx.vout.at(nInput),  1,  -1,  true,  true,  true,  0,  false,  0);
    BOOST_CHECK_EQUAL(output5.GetEffectiveValue(), nValue); 
}
BOOST_AUTO_TEST_CASE(SelectCoins_effective_value_test)