code: function isRelated(a, b) {
    if (a.measurementAvg === b.measurementAvg) return true;
    if (a.relatedNames &&
        a.relatedNames.has(b.measurementAvg)) {
      return true;
    }
    if (b.relatedNames &&
        b.relatedNames.has(a.measurementAvg)) {
      return true;
    }
    return false;
  }
docs: Two Alerts are related if either
  A) their measurements are equal, or
  B) either's relatedNames contains the other's measurement.
  
  @param {!Alert} a
  @param {!Alert} b
  @return {boolean}