a warning is logged if the `log` method is used with an unknown log-level
this happens whenever people confuse the `log` method with yet another log-level-short method (like in the browser console.log)
adjusted `newLevel-test` accordingly
rel: https://github.com/log4js-node/log4js-node/issues/1042
Signed-off-by: abernh <a.bernhard@23go.de>