message: Use safe defaults for calcite diff/regressions policies
diff: const fs = require('fs');
  const path = require('path');
  +const defaultDatapointPolicies = {
  + // Median is a safe default to use, see https://doc.calcite.siliceum.com/performance/stability/statistics.html#descriptive-statistics for why we do not pick the mean.
  + aggregationPolicy: 'median',
  + // We want to consider only significant changes, in our case meaning 20% increase of the median.
  + // We chose 20% as a safe default since even when stabilized, a CPU can have such variations due to (for example) the Intel JCC Erratum. (https://www.intel.com/content/dam/support/us/en/documents/processors/mitigations-jump-conditional-code-erratum.pdf)
  + // We can at a later point in time lower this value if benchmarks are stable enough.
  + // See https://doc.calcite.siliceum.com/performance/stability/index.html for a reference of what can impact stability.
  + diffPolicy: 'relativeDifference',
  + regressionPolicy: 'lessIsBetter',
  + regressionArgument: 20
  +};
  +
  const fromGoogleBenchFile = (filePath, builder, calciteContext) => {
  const data = calciteContext.readJson(filePath);
  @@ -13,6 +25,7 @@ const fromGoogleBenchFile = (filePath, builder, calciteContext) => {
  'real_time', {
  values: [bench['real_time']],
  unit: bench['time_unit'],
  + ...defaultDatapointPolicies
  }
  );
  @@ -22,6 +35,7 @@ const fromGoogleBenchFile = (filePath, builder, calciteContext) => {
  'cpu_time', {
  values: [bench['cpu_time']],
  unit: bench['time_unit'],
  + ...defaultDatapointPolicies
  }
  );
  });
  