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).
{
    LOCK(cs_wallet);
    error.clear();
    bool result = false;
    auto spk_man = GetScriptPubKeyMan(type, false );
    if (spk_man) {
        spk_man->TopUp();
        result = spk_man->GetNewDestination(type, dest, error);
    }
    if (result) {
        SetAddressBook(dest, label, "receive");
    }
    return result;
}
bool CWallet::GetNewChangeDestination(const OutputType type, CTxDestination& dest, std::string& error)
{
    LOCK(cs_wallet);
    error.clear();
    ReserveDestination reservedest(this, type);
    if (!reservedest.GetReservedDestination(dest, true)) {
        error = "Error: Keypool ran out, please call keypoolrefill first";
        return false;
    }
    reservedest.KeepDestination();
    return true;
}
int64_t CWallet::GetOldestKeyPoolTime() const