When running test_bdb.py as a script, `import test_module` would be
importing the existing Lib/test/test_modules.py instead of the
tempcwd/test_module.py module which was dynamically created by
test_bdb.py itself.
(cherry picked from commit 54fd4550)
Co-authored-by: Alex H <1884912+lajarre@users.noreply.github.com>