test_vicious_descriptor_nonsense() started to fails randomly:

$ ./python -m test -j0 -F test_descr test_descr test_descr test_descr test_descr test_descr
Run tests in parallel using 10 child processes
0:00:03 load avg: 1.24 [1/6] test_descr passed
0:00:03 load avg: 1.70 [2/6/1] test_descr failed
test test_descr failed -- Traceback (most recent call last):
  File "/home/vstinner/prog/python/master/Lib/test/test_descr.py", line 4341, in test_vicious_descriptor_nonsense
    self.assertEqual(c.attr, 1)
  File "/home/vstinner/prog/python/master/Lib/test/test_descr.py", line 4328, in __eq__
    del C.attr
AttributeError: attr
0:00:03 load avg: 1.70 [3/6/1] test_descr passed
0:00:04 load avg: 1.70 [4/6/1] test_descr passed
0:00:04 load avg: 1.70 [5/6/1] test_descr passed
0:00:04 load avg: 1.70 [6/6/1] test_descr passed

== Tests result: FAILURE ==

5 tests OK.

1 test failed:
    test_descr

Total duration: 4 sec 213 ms
Tests result: FAILURE

--

It seems like it's a regression introduced by this change:

a24107b04c1277e3c1105f98aff5bfa3a98b33a0 is the first bad commit
commit a24107b04c1277e3c1105f98aff5bfa3a98b33a0
Author: Serhiy Storchaka <storchaka@gmail.com>
Date:   Mon Feb 25 17:59:46 2019 +0200

    bpo-35459: Use PyDict_GetItemWithError() instead of PyDict_GetItem(). (GH-11112)

:040000 040000 da22597a443c84fb29588a3557f5dd04e292a1cc fb73df9fbfdc1893e9f0bde9fbc6ab6febabbe8f M	Include
:040000 040000 4b26a84a0e3a813470e34ddef29596da41d3d28f ca6192ea98e014434a32e2a114e42b297408ce00 M	Modules
:040000 040000 b2dd7d4e832c64ba44781a34093c5d69ea127932 26bfeced0b5776634051ed57d701361252c6de68 M	Objects
:040000 040000 6b5a0bf3a25434ee3de5c9dae3e880217773c0fb 56265d6d2cd8cb92ba47541909af2edec46196e6 M	Python