Opening two of the same wallet (tested in v0.18.0 of bitcoin-qt 64 bit) will cause a database collision, and will crash the program.

`[marshall@likon] {21:21} [~] $ bitcoin-0.18.0/bin/bitcoin-qt `
`terminate called after throwing an instance of 'std::runtime_error'  what():  BerkeleyBatch: Can't open database 8204388-wallet.dat (duplicates fileid 8b1c090000000800e25686350000000000000000 from 1352491-wallet.dat)`
`Aborted (core dumped)`

I have been able to reproduce the issue by importing two of the same wallet (with different filenames).
std::set<CInputCoin>& setCoinsRet, CAmount& nValueRet, const CoinSelectionParams& coin_selection_params, bool& bnb_used) const
{
    setCoinsRet.clear();
    nValueRet = 0;
    std::vector<OutputGroup> utxo_pool;
    if (coin_selection_params.use_bnb) {
        
        FeeCalculation feeCalc;
        CCoinControl temp;
        temp.m_confirm_target = 1008;
        CFeeRate long_term_feerate = GetMinimumFeeRate(*this, temp, &feeCalc);
        
        CAmount cost_of_change = GetDiscardRate(*this).GetFee(coin_selection_params.change_spend_size) + coin_selection_params.effective_fee.GetFee(coin_selection_params.change_output_size);
        
        for (OutputGroup& group : groups) {
            if (!group.EligibleForSpending(eligibility_filter)) continue;
            group.fee = 0;
            group.long_term_fee = 0;
            group.effective_value = 0;
            for (auto it = group.m_outputs.begin(); it != group.m_outputs.end(); ) {
                const CInputCoin& coin = *it;
                CAmount effective_value = coin.txout.nValue - (coin.m_input_bytes < 0 ? 0 : coin_selection_params.effective_fee.GetFee(coin.m_input_bytes));