Merge #20522: [test] Fix sync issue in disconnect_p2ps

3ebde21 [test] Fix wait condition in disconnect_p2ps (Amiti Uttarwar)

Pull request description:

  #19315 currently has a [test failure](https://cirrus-ci.com/task/4545582645641216) because of a race. `disconnect_p2ps` is intended to have a `wait_until` clause that prevents this race, but the conditional doesn't match since its comparing two different object types. `MY_SUBVERSION` is defined in messages.py as a byte string, but is compared to the value returned by the RPC. This PR simply converts types to ensure they match, which should prevent the race from occurring.

  HUGE PROPS TO jnewbery for discovering the issue 🔎

ACKs for top commit:
  jnewbery:
    ACK 3ebde21
  glozow:
    Code review ACK bitcoin/bitcoin@3ebde21

Tree-SHA512: ca096b80a3e4d757a645f38846d6dc89d6a3d35c3435513a72d278e305faddd4aff9e75a767941b51b2abbf59c82679bac1e9a0140d6f285efe3053e51bcc2a8

test/functional/test_framework/test_node.py

@@ -544,7 +544,7 @@ def add_p2p_connection(self, p2p_conn, *, wait_for_verack=True, **kwargs):
 
     def num_test_p2p_connections(self):
         """Return number of test framework p2p connections to the node."""
-        return len([peer for peer in self.getpeerinfo() if peer['subver'] == MY_SUBVERSION])
+        return len([peer for peer in self.getpeerinfo() if peer['subver'] == MY_SUBVERSION.decode("utf-8")])
 
     def disconnect_p2ps(self):
         """Close all p2p connections to the node."""