Revert "A/B fasta performance measurement harness"

pkg/front_end/tool/fasta/standard_deviation.dart

-import 'dart:math';
-
-double average(List<double> elapsedTimes) {
-  return elapsedTimes.reduce((v, e) => v + e) / elapsedTimes.length;
-}
-
-double standardDeviation(double mean, List<double> elapsedTimes) {
-  double numerator = 0.0;
-  for (double elapseTime in elapsedTimes) {
-    numerator += (elapseTime - mean) * (elapseTime - mean);
-  }
-  double stdDev = sqrt(numerator / (elapsedTimes.length - 1));
-  return stdDev;
-}
-
-double standardDeviationOfTheMean(List<double> elapsedTimes, double stdDev) {
-  return stdDev / sqrt(elapsedTimes.length);
-}