code: function calculateStatsPerRun(results) {
      return results.reduce((stat, result) => {
          stat.errorCount += result.errorCount;
          stat.warningCount += result.warningCount;
          stat.fixableErrorCount += result.fixableErrorCount;
          stat.fixableWarningCount += result.fixableWarningCount;
          return stat;
      }, {
          errorCount: 0,
          warningCount: 0,
          fixableErrorCount: 0,
          fixableWarningCount: 0
      });
  }
docs: It will calculate the error and warning count for collection of results from all files
  @param {Object[]} results - Collection of messages from all the files
  @returns {Object} Contains the stats
  @private