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).
{
    SignatureData sigdata;
    CScript script_pub_key = GetScriptForDestination(pkhash);
    for (const auto& spk_man_pair : m_spk_managers) {
        if (spk_man_pair.second->CanProvide(script_pub_key, sigdata)) {
            return spk_man_pair.second->SignMessage(message, pkhash, str_sig);
        }
    }
    return SigningResult::PRIVATE_KEY_NOT_AVAILABLE;
}
bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nChangePosInOut, std::string& strFailReason, bool lockUnspents, const std::set<int>& setSubtractFeeFromOutputs, CCoinControl coinControl)
{
    std::vector<CRecipient> vecSend;
    
    for (size_t idx = 0; idx < tx.vout.size(); idx++) {
        const CTxOut& txOut = tx.vout[idx];
        CRecipient recipient = {txOut.scriptPubKey, txOut.nValue, setSubtractFeeFromOutputs.count(idx) == 1};
        vecSend.push_back(recipient);
    }
    coinControl.fAllowOtherInputs = true;
    for (const CTxIn& txin : tx.vin) {