qa: Intermittent failure in p2p_leak.py #22085

On master (5c041cb348e667672c8b5ed504dba05adf60783b) Linux32 build (https://bitcoinbuilds.org/index.php?ansilog=d7b3e075-683a-45cc-94d4-9645fc17e0b6.log#l2917):

<details><summary>log excerpt</summary> <p>

L2916   150/205 - p2p_leak.py failed, Duration: 7 s
L2917   
L2918   stdout:
L2919   2021-05-27T12:28:03.208000Z TestFramework (INFO): Initializing test directory /tmp/test_runner_₿_🏃_20210527_080707/p2p_leak_52
L2920   2021-05-27T12:28:03.999000Z TestFramework (INFO): Check that the node doesn't send unexpected messages before handshake completion
L2921   2021-05-27T12:28:09.013000Z TestFramework (ERROR): Assertion failed
L2922   Traceback (most recent call last):
L2923     File "/home/ubuntu/src/test/functional/test_framework/test_framework.py", line 128, in main
L2924       self.run_test()
L2925     File "/home/ubuntu/src/test/functional/p2p_leak.py", line 153, in run_test
L2926       assert not no_version_idle_peer.is_connected
L2927   AssertionError
L2928   2021-05-27T12:28:09.065000Z TestFramework (INFO): Stopping nodes
L2929   2021-05-27T12:28:09.567000Z TestFramework (WARNING): Not cleaning up dir /tmp/test_runner_₿_🏃_20210527_080707/p2p_leak_52
L2930   2021-05-27T12:28:09.567000Z TestFramework (ERROR): Test failed. Test logging available at /tmp/test_runner_₿_🏃_20210527_080707/p2p_leak_52/test_framework.log
L2931   2021-05-27T12:28:09.568000Z TestFramework (ERROR): 
L2932   2021-05-27T12:28:09.568000Z TestFramework (ERROR): Hint: Call /home/ubuntu/src/test/functional/combine_logs.py '/tmp/test_runner_₿_🏃_20210527_080707/p2p_leak_52' to consolidate all logs
L2933   2021-05-27T12:28:09.568000Z TestFramework (ERROR): 
L2934   2021-05-27T12:28:09.568000Z TestFramework (ERROR): If this failure happened unexpectedly or intermittently, please file a bug and provide a link or upload of the combined log.
L2935   2021-05-27T12:28:09.568000Z TestFramework (ERROR): https://github.com/bitcoin/bitcoin/issues
L2936   2021-05-27T12:28:09.568000Z TestFramework (ERROR):

</p> </details>

On master (be1c512437f7aa8215d2e05eda5cc8b58c3d3937) Linux x86_64 build:

151/206 - p2p_leak.py failed, Duration: 7 s

stdout:
2021-05-29T14:54:03.235000Z TestFramework (INFO): Initializing test directory /tmp/test_runner_₿_🏃_20210529_103437/p2p_leak_52
2021-05-29T14:54:04.026000Z TestFramework (INFO): Check that the node doesn't send unexpected messages before handshake completion
2021-05-29T14:54:09.041000Z TestFramework (ERROR): Assertion failed
Traceback (most recent call last):
  File "/home/ubuntu/src/test/functional/test_framework/test_framework.py", line 128, in main
    self.run_test()
  File "/home/ubuntu/src/test/functional/p2p_leak.py", line 153, in run_test
    assert not no_version_idle_peer.is_connected
AssertionError
2021-05-29T14:54:09.093000Z TestFramework (INFO): Stopping nodes