Reported here: https://github.com/bitcoin/bitcoin/pull/10244#issuecomment-378035305

Travis log here: https://travis-ci.org/bitcoin/bitcoin/jobs/361243719#L2810

Note the JSON exception:

```
test_framework.authproxy.JSONRPCException: The mempool was not loaded yet (-1) 
```

That exception was introduced here: https://github.com/bitcoin/bitcoin/commit/cb1e319fe9e198c9c5cf5236fe9af5a3d748b9e8#diff-a0c8f511d90e83aa9b5857e819ced344R1617

cc @jtimon 
CTxMemPool::setEntries setChildrenCheck;
        auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetHash(), 0));
        uint64_t child_sizes = 0;
        for (; iter != mapNextTx.end() && iter->first->hash == it->GetTx().GetHash(); ++iter) {
            txiter childit = mapTx.find(iter->second->GetHash());
            assert(childit != mapTx.end()); 
            if (setChildrenCheck.insert(childit).second) {
                child_sizes += childit->GetTxSize();
            }
        }
        assert(setChildrenCheck == GetMemPoolChildren(it));
        
        
        assert(it->GetSizeWithDescendants() >= child_sizes + it->GetTxSize());
        if (fDependsWait)
            waitingOnDependants.push_back(&(*it));
        else {
            CheckInputsAndUpdateCoins(tx, mempoolDuplicate, spendheight);
        }
    }
    unsigned int stepsSinceLastRemove = 0;
    while (!waitingOnDependants.empty()) {
        const CTxMemPoolEntry* entry = waitingOnDependants.front();
        waitingOnDependants.pop_front();
        if (!mempoolDuplicate.HaveInputs(entry->GetTx())) {
            waitingOnDependants.push_back(entry);
            stepsSinceLastRemove++;
            assert(stepsSinceLastRemove < waitingOnDependants.size());
        } else {