test_argparse leaks references (regression)

The commit 328dbc051f84bd5fdf61101bb4fa61d85f8b7feb of gh-85567 introduced a reference leak:

```
$ ./python -m test --matchfile=bisect -R 3:3 test_argparse 
(...)
test_argparse leaked [24, 24, 24] references, sum=72
(...)
```