test_functools sometimes leaks references

[Eclips4]

The text below is a part of the refleak tests, and unfortunately, I am unable to constantly reproduce it :(

0:13:26 load avg: 7.84 [201/478/1] test_functools failed (reference leak) -- running (3): test.test_multiprocessing_spawn.test_processes (7 min 14 sec), test_embed (1 min 12 sec), test_faulthandler (55.3 sec)
beginning 6 repetitions. Showing number of leaks (. for 0 or less, X for 10 or more)
123:456
XX1 111

[adiaholic]

I was able to reproduce this:

0:00:00 load avg: 1.70 Run 1 test sequentially in a single process 0:00:00 load avg: 1.70 [1/1] test_functools beginning 6 repetitions. Showing number of leaks (. for 0 or less, X for 10 or more)
123:456
XX. 3..
test_functools leaked [3, 0, 0] memory blocks, sum=3 (this is fine)

[adiaholic]

@Eclips4, I stumbled upon this which suggests that this scenario might be false positive and an outcome of late initialization and not a real leak. Since it is false positive it is difficult to constantly reproduce it.
If this needs further attention please let me know, I'm happy to look into it more if you suggest so :)

[vstinner]

Previous issue: #80741