Chore: Remove betterer:merge and revert previous changes to betterer:stats (#98609)

scripts/cli/reportBettererStats.ts

@@ -0,0 +1,34 @@
+import { betterer } from '@betterer/betterer';
+import { camelCase } from 'lodash';
+
+function logStat(name: string, value: number) {
+  // Note that this output format must match the parsing in ci-frontend-metrics.sh
+  // which expects the two values to be separated by a space
+  console.log(`${name} ${value}`);
+}
+
+async function main() {
+  const results = await betterer.results();
+
+  for (const testResults of results.resultSummaries) {
+    const countByMessage = {};
+    const name = camelCase(testResults.name);
+    Object.values(testResults.details)
+      .flatMap((v) => v)
+      .forEach((detail) => {
+        const message = camelCase(detail.message);
+        const metricName = `${name}_${message}`;
+        if (metricName in countByMessage) {
+          countByMessage[metricName]++;
+        } else {
+          countByMessage[metricName] = 1;
+        }
+      });
+
+    for (const [metricName, count] of Object.entries<number>(countByMessage)) {
+      logStat(metricName, count);
+    }
+  }
+}
+
+main().catch(console.error);