I was messing around with min relay policies and found that under certain circumstances the mempool will accept things, then not relay to any peers.

Example made using wallet:
Transaction of size 6195, fee of 619 satoshis, minrelay of 100 satoshis per kvB. Mempool logic allows it:

```
        // No transactions are allowed below minRelayTxFee except from disconnected blocks
        if (!bypass_limits && nModifiedFees < ::minRelayTxFee.GetFee(nSize)) {
            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "min relay fee not met", false, strprintf("%d < %d", nModifiedFees, ::minRelayTxFee.GetFee(nSize)));
        }
```
and lets it into mempool

but in net_processing.cpp:

```
                    if (filterrate && txinfo.feeRate.GetFeePerK() < filterrate) {
                        continue;
                    }
```
this gets hit because the computed feerate is insufficient(printing I added):
```
0.00000099 BTC/kB
```

I'm not super at arithmetic so I'm opening this up in case someone has an easy fix. 

let me also get a reproducible test failure with this...
LOCK(cs);
    
    return memusage::MallocUsage(sizeof(CTxMemPoolEntry) + 12 * sizeof(void*)) * mapTx.size() + memusage::DynamicUsage(mapNextTx) + memusage::DynamicUsage(mapDeltas) + memusage::DynamicUsage(mapLinks) + memusage::DynamicUsage(vTxHashes) + cachedInnerUsage;
}
void CTxMemPool::RemoveStaged(setEntries &stage, bool updateDescendants, MemPoolRemovalReason reason) {
    AssertLockHeld(cs);
    UpdateForRemoveFromMempool(stage, updateDescendants);
    for (txiter it : stage) {
        removeUnchecked(it, reason);
    }
}
int CTxMemPool::Expire(std::chrono::seconds time)
{
    AssertLockHeld(cs);
    indexed_transaction_set::index<entry_time>::type::iterator it = mapTx.get<entry_time>().begin();
    setEntries toremove;
    while (it != mapTx.get<entry_time>().end() && it->GetTime() < time) {
        toremove.insert(mapTx.project<0>(it));
        it++;
    }
    setEntries stage;
    for (txiter removeit : toremove) {
        CalculateDescendants(removeit, stage);
    }
    RemoveStaged(stage, false, MemPoolRemovalReason::EXPIRY);
    return stage.size();
}
void CTxMemPool::addUnchecked(const CTxMemPoolEntry &entry, bool validFeeEstimate)