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).
{
    CAmount nCredit = 0;
    for (const CTxOut& txout : tx.vout)
    {
        nCredit += GetCredit(txout, filter);
        if (!MoneyRange(nCredit))
            throw std::runtime_error(std::string(__func__) + ": value out of range");
    }
    return nCredit;
}
CAmount CWallet::GetChange(const CTransaction& tx) const
{
    CAmount nChange = 0;
    for (const CTxOut& txout : tx.vout)
    {
        nChange += GetChange(txout);
        if (!MoneyRange(nChange))
            throw std::runtime_error(std::string(__func__) + ": value out of range");
    }
    return nChange;
}
bool CWallet::IsHDEnabled() const