aarch64 RHEL8 Refleaks 3.x:
https://buildbot.python.org/all/#/builders/563/builds/127

The system load was quite high (9.95) for "CPU count: 8".

0:22:19 load avg: 9.95 [406/426/2] test_socket failed (env changed) (2 min 41 sec) -- running: test_pydoc (20 min 35 sec), test_asyncio (11 min 56 sec), test_faulthandler (39.2 sec), test_concurrent_futures (20 min 7 sec), test_venv (1 min 17 sec), test_peg_generator (15 min 51 sec), test_multiprocessing_spawn (54.4 sec), test_signal (9 min 26 sec)
beginning 6 repetitions
123456
....Warning -- threading_cleanup() failed to cleanup 0 threads (count: 0, dangling: 5)
Warning -- Dangling thread: <Thread(Thread-30, stopped 281473491857888)>
Warning -- Dangling thread: <Thread(Thread-29, stopped 281473491857888)>
Warning -- Dangling thread: <Thread(Thread-32, stopped 281473491857888)>
Warning -- Dangling thread: <Thread(Thread-31, stopped 281473491857888)>
Warning -- Dangling thread: <_MainThread(MainThread, started 281473770473840)>
..

It may be related to bpo-36750: "test_socket leaks file descriptors on macOS".