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).
}
            if (rescan_height != block_height) {
                error = _("Prune: last wallet synchronisation goes beyond pruned data. You need to -reindex (download the whole blockchain again in case of pruned node)").translated;
                return nullptr;
            }
        }
        chain.initMessage(_("Rescanning...").translated);
        walletInstance->WalletLogPrintf("Rescanning last %i blocks (from block %i)...\n", *tip_height - rescan_height, rescan_height);
        
        
        
        Optional<int64_t> time_first_key = MakeOptional(false, int64_t());;
        for (auto spk_man : walletInstance->GetAllScriptPubKeyMans()) {
            int64_t time = spk_man->GetTimeFirstKey();
            if (!time_first_key || time < *time_first_key) time_first_key = time;
        }
        if (time_first_key) {
            if (Optional<int> first_block = locked_chain->findFirstBlockWithTimeAndHeight(*time_first_key - TIMESTAMP_WINDOW, rescan_height, nullptr)) {
                rescan_height = *first_block;
            }
        }
        {
            WalletRescanReserver reserver(walletInstance.get());
            if (!reserver.reserve() || (ScanResult::SUCCESS != walletInstance->ScanForWalletTransactions(locked_chain->getBlockHash(rescan_height), {} , reserver, true ).status)) {
                error = _("Failed to rescan the wallet during initialization").translated;
                return nullptr;
            }
        }
        walletInstance->chainStateFlushed(locked_chain->getTipLocator());
        walletInstance->database->IncrementUpdateCounter();