partial bitcoin#26448: fix intermittent failure in p2p_sendtxrcncl.py

contains:
- 74d9753 (changes to `test_node.py`)

Author: kwvg

test/functional/test_framework/test_node.py

@@ -651,6 +651,10 @@ def add_outbound_p2p_connection(self, p2p_conn, *, wait_for_verack=True, p2p_idx
 
         This method adds the p2p connection to the self.p2ps list and returns
         the connection to the caller.
+
+        p2p_idx must be different for simultaneously connected peers. When reusing it for the next peer
+        after disconnecting the previous one, it is necessary to wait for the disconnect to finish to avoid
+        a race condition.
         """
 
         def addconnection_callback(address, port):