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).
{
    QMutexLocker locker(&m_mutex);
    std::map<std::string, bool> wallets;
    for (const std::string& name : m_node.listWalletDir()) {
        wallets[name] = false;
    }
    for (WalletModel* wallet_model : m_wallets) {
        auto it = wallets.find(wallet_model->wallet().getWalletName());
        if (it != wallets.end()) it->second = true;
    }
    return wallets;
}
void WalletController::closeWallet(WalletModel* wallet_model, QWidget* parent)
{
    QMessageBox box(parent);
    box.setWindowTitle(tr("Close wallet"));
    box.setText(tr("Are you sure you wish to close the wallet <i>%1</i>?").arg(GUIUtil::HtmlEscape(wallet_model->getDisplayName())));
    box.setInformativeText(tr("Closing the wallet for too long can result in having to resync the entire chain if pruning is enabled."));
    box.setStandardButtons(QMessageBox::Yes|QMessageBox::Cancel);
    box.setDefaultButton(QMessageBox::Yes);
    if (box.exec() != QMessageBox::Yes) return;
    
    wallet_model->wallet().remove();
    
    removeAndDeleteWallet(wallet_model);
}
WalletModel* WalletController::getOrCreateWallet(std::unique_ptr<interfaces::Wallet> wallet)