AMD64 Fedora Rawhide Refleaks 3.x:
https://buildbot.python.org/all/#/builders/565/builds/11

test_interpreters leaked [1424, 1422, 1424] references, sum=4270

According to git bisect, the leak was introduced by:

commit 71d1bd9569c8a497e279f2fea6fe47cd70a87ea3
Author: Mohamed Koubaa <koubaa.m@gmail.com>
Date:   Thu Sep 3 03:21:06 2020 -0500

    bpo-1635741: Port _signal module to multi-phase init (PEP 489) (GH-22049)

 .../2020-09-01-17-07-20.bpo-1635741.7wSuCc.rst     |   1 +
 Modules/signalmodule.c                             | 168 +++++++++++----------
 2 files changed, 87 insertions(+), 82 deletions(-)


Example of leak:

$ ./python -m test -R 3:3 test_interpreters -m test.test_interpreters.TestInterpreterClose.test_from_current
0:00:00 load avg: 0.72 Run tests sequentially
0:00:00 load avg: 0.72 [1/1] test_interpreters
beginning 6 repetitions
123456
......
test_interpreters leaked [237, 237, 237] references, sum=711
test_interpreters leaked [18, 18, 18] memory blocks, sum=54
test_interpreters failed

== Tests result: FAILURE ==

1 test failed:
    test_interpreters

Total duration: 1.1 sec
Tests result: FAILURE