benchmark_harness

• Require Dart 3.2.

• Add PerfBenchmarkBase class which runs the 'perf stat' command from linux-tools on a benchmark and reports metrics from the hardware performance counters and the iteration count, as well as the run time measurement reported by BenchmarkBase.

Full Changelog: https://github.com/dart-lang/benchmark_harness/compare/v2.2.2...v2.2.3

• Added package topics to the pubspec file.
• Require Dart 2.19.

• Improve convergence speed of BenchmarkBase measuring algorithm by allowing some degree of measuring jitter.

• Change measuring algorithm in BenchmarkBase to avoid calling stopwatch
  methods repeatedly in the measuring loop. This makes measurement work better
  for run methods which are small themselves.