htlcswitch: skip checking replays for reforwarded packets

We now rely on the forwarding package's state to decide whether a given
packet is a reforwarding or not. If we know it's a reforwarding packet,
there's no need to check for replays in the `sharedHashes` bucket, which
behaves the same as if we are querying the `batchReplayBkt`.

htlcswitch/mock.go

@@ -522,7 +522,7 @@ func (p *mockIteratorDecoder) DecodeHopIterator(r io.Reader, rHash []byte,
 }
 
 func (p *mockIteratorDecoder) DecodeHopIterators(id []byte,
-	reqs []hop.DecodeHopIteratorRequest) (
+	reqs []hop.DecodeHopIteratorRequest, _ bool) (
 	[]hop.DecodeHopIteratorResponse, error) {
 
 	idHash := sha256.Sum256(id)