1. Moving the _create_config and create_config functions from build_fuzzers_test.py and run_fuzzers_test.py into test_helpers.py (which is now part of cifuzz instead of infra) and share code between them.
2. Rename artifacts_dir to crashes_dir in run_fuzzers.py. "artifacts" is ambiguous.
3. Make some small changes to pytest.ini to improve debugging.
jonathanmetzman