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).
class PlatformStyle;
class WalletModel;
namespace interfaces {
class Handler;
class Node;
class Wallet;
} 
class AskPassphraseDialog;
class CreateWalletActivity;
class CreateWalletDialog;
class OpenWalletActivity;
class WalletControllerActivity;
/**
 * Controller between interfaces::Node, WalletModel instances and the GUI.
 */
class WalletController : public QObject