Add lint targets back to `lint.sh`, if not configurable

[DMRobertson]

A few of us have been bitten by #12420, e.g. by linting virtualenvs locally. Before, we were using the list of lint targets both to exclude unwanted lintees and include missed lintees. #12107 means that all the desired lint targets are easily discoverable by CI, but it's still convenient to exclude unwanted directories from local linting.