`bitcoin-cli loadwallet "wallet.dat"` command causes bitcoind crash

log info:
```
bitcoind: wallet/db.cpp:236: BerkeleyEnvironment::VerifyResult BerkeleyEnvironment::Verify(const string&, BerkeleyEnvironment::recoverFunc_type, std::__cxx11::string&): Assertion `mapFileUseCount.count(strFile) == 0' failed.
Aborted (core dumped)
```

Bitcoin Core Daemon version `v0.17.0.0-ge1ed37edaedc85b8c3468bd9a726046344036243`

{
    if (fDbEnvInit)
        throw std::runtime_error("BerkeleyEnvironment::MakeMock: Already initialized");
    boost::this_thread::interruption_point();
    LogPrint(BCLog::DB, "BerkeleyEnvironment::MakeMock\n");
    dbenv->set_cachesize(1, 0, 1);
    dbenv->set_lg_bsize(10485760 * 4);
    dbenv->set_lg_max(10485760);
    dbenv->set_lk_max_locks(10000);
    dbenv->set_lk_max_objects(10000);
    dbenv->set_flags(DB_AUTO_COMMIT, 1);
    dbenv->log_set_config(DB_LOG_IN_MEMORY, 1);
    int ret = dbenv->open(nullptr,
                         DB_CREATE |
                             DB_INIT_LOCK |
                             DB_INIT_LOG |
                             DB_INIT_MPOOL |
                             DB_INIT_TXN |
                             DB_THREAD |
                             DB_PRIVATE,
                         S_IRUSR | S_IWUSR);
    if (ret > 0)
        throw std::runtime_error(strprintf("BerkeleyEnvironment::MakeMock: Error %d opening database environment.", ret));
    fDbEnvInit = true;
    fMockDb = true;
}
BerkeleyEnvironment::VerifyResult BerkeleyEnvironment::Verify(const std::string& strFile, recoverFunc_type recoverFunc, std::string& out_backup_filename)