Indeed, that fixes the problem in at least 2 modules:
./python -m test test_atexit -R :
0:00:00 load avg: 0.84 Run tests sequentially
0:00:00 load avg: 0.84 [1/1] test_atexit
beginning 9 repetitions
123456789
.........
== Tests result: SUCCESS ==
1 test OK.
Total duration: 1.5 sec
Tests result: SUCCESS
./python -m test test_capi -R :
0:00:00 load avg: 1.19 Run tests sequentially
0:00:00 load avg: 1.19 [1/1] test_capi
beginning 9 repetitions
123456789
..........
test_capi passed in 2 min 8 sec
== Tests result: SUCCESS ==
1 test OK.
Total duration: 2 min 8 sec
Tests result: SUCCESS
Although the rest of the tests still leak, so there is something else :(