test_import leaks references

[carljm]

Bug report

Checklist

• I am confident this is a bug in CPython, not a bug in a third-party project
• I have searched the CPython issue tracker,
  and am confident this bug has not been reported before

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Output from running 'python -VV' on the command line:

Python 3.13.0a0 (bisect/good-edb569e8e1f469ac5ce629cc647ab169d895de41-1-gfeb9a49c9c-dirty:feb9a49) [GCC 8.5.0 20210514 (Red Hat 8.5.0-20)]

A clear and concise description of the bug:

Reproduce with ./python -m test -R: -v test_import.

Linked PRs

• gh-108696: revert bypassing import cache in test_import helper #108698

[carljm]

Bisection shows this leak was introduced by #104186

cc @FFY00

[sunmy2019]

Checks passed