When I run `scantxoutset` via RPC using big range (e.g. 10000) on XPUB, the progress report indicator (`scantxoutset status`) reports 100% at start (while the keys are being derived). This is most probably the result of the previous operation. The progress is only reset to zero when the actual scan starts. I would expect the progress is set to zero before the keys are being derived.

Output of periodic calls to `scantxoutset status` while performing long operation.

```
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 0 }
{ progress: 3 }
{ progress: 6 }
{ progress: 9 }
{ progress: 12 }
{ progress: 15 }
{ progress: 17 }
{ progress: 20 }
{ progress: 23 }
{ progress: 26 }
{ progress: 29 }
{ progress: 32 }
{ progress: 35 }
{ progress: 37 }
{ progress: 40 }
{ progress: 43 }
{ progress: 46 }
{ progress: 49 }
{ progress: 51 }
{ progress: 54 }
{ progress: 57 }
{ progress: 60 }
{ progress: 63 }
{ progress: 66 }
{ progress: 68 }
{ progress: 71 }
{ progress: 74 }
{ progress: 77 }
{ progress: 80 }
{ progress: 82 }
{ progress: 85 }
{ progress: 88 }
{ progress: 91 }
{ progress: 94 }
{ progress: 97 }
{ progress: 100 }
```
ret_all.pushKV("mintxsize", mintxsize == MAX_BLOCK_SERIALIZED_SIZE ? 0 : mintxsize);
    ret_all.pushKV("outs", outputs);
    ret_all.pushKV("subsidy", GetBlockSubsidy(pindex->nHeight, Params().GetConsensus()));
    ret_all.pushKV("swtotal_size", swtotal_size);
    ret_all.pushKV("swtotal_weight", swtotal_weight);
    ret_all.pushKV("swtxs", swtxs);
    ret_all.pushKV("time", pindex->GetBlockTime());
    ret_all.pushKV("total_out", total_out);
    ret_all.pushKV("total_size", total_size);
    ret_all.pushKV("total_weight", total_weight);
    ret_all.pushKV("totalfee", totalfee);
    ret_all.pushKV("txs", (int64_t)block.vtx.size());
    ret_all.pushKV("utxo_increase", outputs - inputs);
    ret_all.pushKV("utxo_size_inc", utxo_size_inc);
    if (do_all) {
        return ret_all;
    }
    UniValue ret(UniValue::VOBJ);
    for (const std::string& stat : stats) {
        const UniValue& value = ret_all[stat];
        if (value.isNull()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid selected statistic %s", stat));
        }
        ret.pushKV(stat, value);
    }
    return ret;
},
    };
}
static RPCHelpMan savemempool()