test: extend FreeBSD ephemeral port range fix to P2P listeners

The previous commit added set_ephemeral_port_range() to
avoid port conflicts on FreeBSD by requesting ports from the high
ephemeral range (49152-65535) instead of the default range
which overlaps with the test framework's static port range.

That fix was applied to the SOCKS5 server but not to P2P listeners
created via NetworkThread.create_listen_server(). This commit extends
the fix to cover P2P listeners as well.

When port=0 is requested (dynamic allocation), we now:
1. Manually create a socket with the appropriate address family
2. Call set_ephemeral_port_range() to configure the port range
3. Bind and listen on the socket
4. Pass the pre-configured socket to asyncio's create_server()

This ensures that dynamically allocated ports for P2P listeners also
come from the high range on FreeBSD, avoiding conflicts with the test
framework's static port assignments.

Co-Authored-By: Vasil Dimov <vd@FreeBSD.org>

test/functional/test_framework/p2p.py

@@ -22,9 +22,11 @@ P2PTxInvStore: A p2p interface class that inherits from P2PDataStore, and keeps
 
 import asyncio
 from collections import defaultdict
+import ipaddress
 from io import BytesIO
 import logging
 import platform
+import socket
 import struct
 import sys
 import threading
@@ -76,6 +78,9 @@ from test_framework.messages import (
     MAGIC_BYTES,
     sha256,
 )
+from test_framework.netutil import (
+    set_ephemeral_port_range,
+)
 from test_framework.util import (
     assert_not_equal,
     MAX_NODES,
@@ -793,8 +798,22 @@ class NetworkThread(threading.Thread):
             # connections, we can accomplish this by providing different
             # `proto` functions
 
-            listener = await cls.network_event_loop.create_server(peer_protocol, addr, port)
-            port = listener.sockets[0].getsockname()[1]
+            if port == 0:
+                # Manually create the socket in order to set the range to be
+                # used for the port before the bind() call.
+                if ipaddress.ip_address(addr).version == 4:
+                    address_family = socket.AF_INET
+                else:
+                    address_family = socket.AF_INET6
+                s = socket.socket(address_family)
+                set_ephemeral_port_range(s)
+                s.bind((addr, 0))
+                s.listen()
+                listener = await cls.network_event_loop.create_server(peer_protocol, sock=s)
+                port = listener.sockets[0].getsockname()[1]
+            else:
+                listener = await cls.network_event_loop.create_server(peer_protocol, addr, port)
+
             logger.debug("Listening server on %s:%d should be started" % (addr, port))
             cls.listeners[(addr, port)] = listener