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 bool include_watch_only = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
    const isminetype is_mine_filter = include_watch_only ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
    for (const COutPoint& output : lockedCoins) {
        auto it = wallet.mapWallet.find(output.hash);
        if (it != wallet.mapWallet.end()) {
            const auto& wtx = it->second;
            int depth = wallet.GetTxDepthInMainChain(wtx);
            if (depth >= 0 && output.n < wtx.tx->vout.size() &&
                wallet.IsMine(wtx.tx->vout[output.n]) == is_mine_filter
            ) {
                CTxDestination address;
                if (ExtractDestination(FindNonChangeParentOutput(wallet, *wtx.tx, output.n).scriptPubKey, address)) {
                    const auto out = wtx.tx->vout.at(output.n);
                    result[address].emplace_back(
                            COutPoint(wtx.GetHash(), output.n), out, depth, CalculateMaximumSignedInputSize(out, &wallet, nullptr),  true,  true,  false, wtx.GetTxTime(), CachedTxIsFromMe(wallet, wtx, ISMINE_ALL));
                }
            }
        }
    }
    return result;
}
std::vector<OutputGroup> GroupOutputs(const CWallet& wallet, const std::vector<COutput>& outputs, const CoinSelectionParams& coin_sel_params, const CoinEligibilityFilter& filter, bool positive_only)
{
    std::vector<OutputGroup> groups_out;
    if (!coin_sel_params.m_avoid_partial_spends) {
        
        for (const COutput& output : outputs) {
            
            if (!output.spendable) continue;