op-e2e: Fix hanging network notify test (#12868)

op-node/p2p/sync_test.go

@@ -360,18 +360,24 @@ func TestNetworkNotifyAddPeerAndRemovePeer(t *testing.T) {
 		return nil
 	}, metrics.NoopMetrics, &NoopApplicationScorer{})
 
-	waitChan := make(chan struct{}, 1)
+	waitChan := make(chan struct{}, 2)
+	var connectedOnce sync.Once
+	var disconnectedOnce sync.Once
 	hostA.Network().Notify(&network.NotifyBundle{
 		ConnectedF: func(nw network.Network, conn network.Conn) {
+			connectedOnce.Do(func() {
 				syncCl.AddPeer(conn.RemotePeer())
 				waitChan <- struct{}{}
+			})
 		},
 		DisconnectedF: func(nw network.Network, conn network.Conn) {
+			disconnectedOnce.Do(func() {
 				// only when no connection is available, we can remove the peer
 				if nw.Connectedness(conn.RemotePeer()) == network.NotConnected {
 					syncCl.RemovePeer(conn.RemotePeer())
 				}
 				waitChan <- struct{}{}
+			})
 		},
 	})
 	syncCl.Start()