pytest: don't assume that join_nodes needs only check ends.

I saw another "only_one()" fail on alias checking: it's not
entirely clear to me with the more aggressive sending of
own gossip, that we necessarily process in order, so we might
not have actually seen all channels just because we saw
the farthest one.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

contrib/pyln-testing/pyln/testing/utils.py

@@ -1452,15 +1452,15 @@ class NodeFactory(object):
 
         bitcoind.generate_block(5)
 
-        # Make sure everyone sees all channels: we can cheat and
-        # simply check the ends (since it's a line).
-        nodes[0].wait_channel_active(scids[-1])
-        nodes[-1].wait_channel_active(scids[0])
-
-        # Make sure we have all node announcements, too (just check ends)
+        # Make sure everyone sees all channels, all other nodes
         for n in nodes:
-            for end in (nodes[0], nodes[-1]):
-                wait_for(lambda: 'alias' in only_one(end.rpc.listnodes(n.info['id'])['nodes']))
+            for scid in scids:
+                n.wait_channel_active(scid)
+
+        # Make sure we have all node announcements, too
+        for n in nodes:
+            for n2 in nodes:
+                wait_for(lambda: 'alias' in only_one(n.rpc.listnodes(n2.info['id'])['nodes']))
 
     def line_graph(self, num_nodes, fundchannel=True, fundamount=FUNDAMOUNT, wait_for_announce=False, opts=None, announce_channels=True):
         """ Create nodes, connect them and optionally fund channels.