test-extension: fix disabled extension tests for run-tests.py --local One test that requires inserting a broken extension into hgext does this by modifying PYTHONPATH. This doesn't work when run with --local because the 'hg' script being used is in the same directory as the local hgext. Instead of modifying PYTHONPATH, a secondary extension is enabled using --config that inserts the dummy hgext at the beginning of sys.path, before the script's path.