Silence tslint on no output (#3121)

Author: joscha

src/runner.ts

@@ -150,7 +150,9 @@ async function runWorker(options: Options, logger: Logger): Promise<Status> {
  }
 
  const { output, errorCount } = await runLinter(options, logger);
- logger.log(output);
+ if (output && output.trim()) {
+ logger.log(output);
+ }
  return options.force || errorCount === 0 ? Status.Ok : Status.LintError;
 }