gh-121359: make clean environment (no PYTHON* vars) for test_pyrepl.TestMain#121672

ambv merged 4 commits intopython:mainpython/cpython:mainfrom

skirpichev:use-clean-env-in-test_pyrepl-121359skirpichev/cpython:use-clean-env-in-test_pyrepl-121359Copy head branch name to clipboard