test: make sure we are on sync with a peer before checking if they have sent a message

p2p_orphan_handling checks whether a message has not been requested slightly
too soon, making the check always succeed. This passes unnoticed since the
expected result is for the message to not have been received, but it will make
the test not catch a relevant change that should make it fail

test/functional/p2p_orphan_handling.py

@@ -113,6 +113,7 @@ class PeerTxRelayer(P2PTxInvStore):
 
     def assert_never_requested(self, txhash):
         """Check that the node has never sent us a getdata for this hash (int type)"""
+        self.sync_with_ping()
         for getdata in self.getdata_received:
             for request in getdata.inv:
                 assert request.hash != txhash