message: test: on node 6.x.x only got 26 v8 metrics
diff: @@ -42,7 +42,7 @@ describe('/test/unit/metrics/node/V8GaugeSet', function () {
  for (const gauge of gauges) {
  data[gauge.name.key] = gauge.metric.getValue();
  }
  - expect(Object.keys(data).length > 28).to.be.true;
  + expect(Object.keys(data).length >= 26).to.be.true;
  for (const key of Object.keys(data)) {
  expect(data[key]).to.be.a('number');
  }
  