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.

#include <consensus/amount.h>
#include <node/context.h>
#include <primitives/transaction.h>
#include <random.h>
#include <test/util/setup_common.h>
#include <util/translation.h>
#include <wallet/coincontrol.h>
#include <wallet/coinselection.h>
#include <wallet/spend.h>
#include <wallet/test/wallet_test_fixture.h>
#include <wallet/wallet.h>
#include <algorithm>
#include <boost/test/unit_test.hpp>
#include <random>
namespace wallet {
BOOST_FIXTURE_TEST_SUITE(coinselector_tests, WalletTestingSetup)
#define RUN_TESTS 100
#define RANDOM_REPEATS 5
typedef std::set<COutput> CoinSet;
static const CoinEligibilityFilter filter_standard(1, 6, 0);
static const CoinEligibilityFilter filter_confirmed(1, 1, 0);
static const CoinEligibilityFilter filter_standard_extra(6, 6, 0);
static int nextLockTime = 0;
static void add_coin(const CAmount& nValue, int nInput, std::vector<COutput>& set)