qa: Avoid start/stop of the network thread mid-test

test/functional/feature_cltv.py

@@ -67,10 +67,6 @@ class BIP65Test(BitcoinTestFramework):
 
     def run_test(self):
         self.nodes[0].add_p2p_connection(P2PInterface())
-
-        network_thread_start()
-
-        # wait_for_verack ensures that the P2P connection is fully up.
         self.nodes[0].p2p.wait_for_verack()
 
         self.log.info("Mining %d blocks", CLTV_HEIGHT - 2)