testsuite: Split up testsuite metric summary
Previously we displayed all metrics in one, long, unintelligible list. Now we make some attempt to split it up by class: decrease, increase, or no-baseline. We also now elide unchanged metrics.
Previously we displayed all metrics in one, long, unintelligible list. Now we make some attempt to split it up by class: decrease, increase, or no-baseline. We also now elide unchanged metrics.