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...
{
    nSizeWithDescendants += modifySize;
    assert(int64_t(nSizeWithDescendants) > 0);
    nModFeesWithDescendants += modifyFee;
    nCountWithDescendants += modifyCount;
    assert(int64_t(nCountWithDescendants) > 0);
}
void CTxMemPoolEntry::UpdateAncestorState(int64_t modifySize, CAmount modifyFee, int64_t modifyCount, int64_t modifySigOps)
{
    nSizeWithAncestors += modifySize;
    assert(int64_t(nSizeWithAncestors) > 0);
    nModFeesWithAncestors += modifyFee;
    nCountWithAncestors += modifyCount;
    assert(int64_t(nCountWithAncestors) > 0);
    nSigOpCostWithAncestors += modifySigOps;
    assert(int(nSigOpCostWithAncestors) >= 0);
}
CTxMemPool::CTxMemPool(CBlockPolicyEstimator* estimator)
    : nTransactionsUpdated(0), minerPolicyEstimator(estimator)
{
    _clear(); 
    
    
    
    nCheckFrequency = 0;
}
bool CTxMemPool::isSpent(const COutPoint& outpoint) const