The commit 8e409cebad42032bb7d0f2cadd8b1e36081d98af introduced a reference leak:
https://buildbot.python.org/all/#/builders/320/builds/71

$ make && ./python -m test test_tempfile -R 3:3
...
test_tempfile leaked [49, 49, 49] references, sum=147
test_tempfile leaked [28, 28, 28] memory blocks, sum=84
...

Single test reproducing the leak:

$ ./python -m test test_tempfile -R 3:3 -m test.test_tempfile.TestGetDefaultTempdir.test_no_files_left_behind
...
test_tempfile leaked [21, 21, 21] references, sum=63
test_tempfile leaked [12, 12, 12] memory blocks, sum=36
...