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 
UniValue ret(UniValue::VOBJ);
    CCoinsStats stats;
    FlushStateToDisk();
    if (GetUTXOStats(pcoinsdbview.get(), stats)) {
        ret.pushKV("height", (int64_t)stats.nHeight);
        ret.pushKV("bestblock", stats.hashBlock.GetHex());
        ret.pushKV("transactions", (int64_t)stats.nTransactions);
        ret.pushKV("txouts", (int64_t)stats.nTransactionOutputs);
        ret.pushKV("bogosize", (int64_t)stats.nBogoSize);
        ret.pushKV("hash_serialized_2", stats.hashSerialized.GetHex());
        ret.pushKV("disk_size", stats.nDiskSize);
        ret.pushKV("total_amount", ValueFromAmount(stats.nTotalAmount));
    } else {
        throw JSONRPCError(RPC_INTERNAL_ERROR, "Unable to read UTXO set");
    }
    return ret;
}
UniValue gettxout(const JSONRPCRequest& request)
{
    if (request.fHelp || request.params.size() < 2 || request.params.size() > 3)
        throw std::runtime_error(
            RPCHelpMan{"gettxout",
                "\nReturns details about an unspent transaction output.\n",
                {
                    {"txid", RPCArg::Type::STR, RPCArg::Optional::NO, "The transaction id"},
                    {"n", RPCArg::Type::NUM, RPCArg::Optional::NO, "vout number"},
                    {"include_mempool", RPCArg::Type::BOOL,  "true", "Whether to include the mempool. Note that an unspent output that is spent in the mempool won't appear."},
                },
                RPCResult{
            "{\n"