Refine performance report

- no longer do the rough benchmark as the internal benchmark has more
  information and appears to be more stable
- try to append the report to the CI job summary to be able to compare runs

.github/workflows/performance-report.yml

@@ -120,20 +120,6 @@ jobs:
           echo "export { rollup as newRollup } from '../../_benchmark/current/rollup.js';" >> ./scripts/perf-report/rollup-artefacts.js
       - name: Run internal benchmark
         run: node --expose-gc scripts/perf-report/index.js
-      - name: Install benchmark tool
-        run: cargo install --locked hyperfine
-      - name: Run Rough benchmark
-        run: |
-          hyperfine --warmup 1 --export-markdown _benchmark/rough-report.md --show-output --runs 3 \
-            'node _benchmark/previous/bin/rollup -i ./perf/entry.js -o _benchmark/result/previous.js' \
-            'node _benchmark/current/bin/rollup -i ./perf/entry.js -o _benchmark/result/current.js'
-      - name: Combine benchmark reports
-        run: |
-          echo "# Performance report!" > _benchmark/result.md
-          echo "## Rough benchmark" >> _benchmark/result.md
-          cat _benchmark/rough-report.md >> _benchmark/result.md
-          echo "## Internal benchmark" >> _benchmark/result.md
-          cat _benchmark/internal-report.md >> _benchmark/result.md
       - name: Find Performance report
         uses: peter-evans/find-comment@v3
         id: findPerformanceReport

scripts/perf-report/report-collector.js

@@ -1,4 +1,4 @@
-import { writeFile } from 'node:fs/promises';
+import { appendFile, writeFile } from 'node:fs/promises';
 import { fileURLToPath } from 'node:url';
 
 export default new (class ReportCollector {
@@ -28,10 +28,12 @@ export default new (class ReportCollector {
 	}
 	outputMsg() {
 		if (process.env.CI) {
-			return writeFile(
-				fileURLToPath(new URL('../../_benchmark/internal-report.md', import.meta.url)),
-				removeAnsiStyles(this.#messageList.join('\n'))
-			);
+			const result = `# Performance report
+${removeAnsiStyles(this.#messageList.join('\n'))}`;
+			return Promise.all([
+				writeFile(fileURLToPath(new URL('../../_benchmark/result.md', import.meta.url)), result),
+				process.env.GITHUB_STEP_SUMMARY && appendFile(process.env.GITHUB_STEP_SUMMARY, result)
+			]);
 		}
 	}
 })();