zmq test: dedup message reception handling in ZMQSubscriber

Summary:
PR description:
> Fixes [[bitcoin/bitcoin#20934 | core#20934]] by using the "sync up" method described in [[bitcoin/bitcoin#20538 | core#20538]].
>
> After improving robustness with this approach (commits 1-3), it turned out that there were still some fails, but those were unrelated to zmq: Out of 500 runs, 3 times sync_mempool() or sync_blocks() timed out, which can happen because the trickle relay time has no upper bound -- hence in rare cases, it takes longer than 60s. This is fixed by enabling immediate tx relay on node1 (commit 4), which as a nice side-effect also gives us a rough 2x speedup for the test.
>
> For further details, also see the explanations in the commit messages.

Note that the changes in commit 4, the speedup from 45s to 14s runtime  using `noban` permissions, were already applied in Bitcoin ABC in D10311.

This is a backport of [[bitcoin/bitcoin#21008 | core#21008]] [1/3]
bitcoin/bitcoin@6014d6e

Depends on D10588

Test Plan: `ninja check-functional`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10589

test/functional/interface_zmq.py

@@ -39,7 +39,8 @@ def __init__(self, socket, topic):
 
         self.socket.setsockopt(zmq.SUBSCRIBE, self.topic)
 
-    def receive(self):
+    # Receive message from publisher and verify that topic and sequence match
+    def _receive_from_publisher_and_check(self):
         topic, body, seq = self.socket.recv_multipart()
         # Topic should match the subscriber topic.
         assert_equal(topic, self.topic)
@@ -48,13 +49,11 @@ def receive(self):
         self.sequence += 1
         return body
 
+    def receive(self):
+        return self._receive_from_publisher_and_check()
+
     def receive_sequence(self):
-        topic, body, seq = self.socket.recv_multipart()
-        # Topic should match the subscriber topic.
-        assert_equal(topic, self.topic)
-        # Sequence should be incremental.
-        assert_equal(struct.unpack('<I', seq)[-1], self.sequence)
-        self.sequence += 1
+        body = self._receive_from_publisher_and_check()
         hash = body[:32].hex()
         label = chr(body[32])
         mempool_sequence = None if len(