Benchmark pr against master to show gain/loss in a more readable way.

.github/workflows/bench.yml

@@ -80,7 +80,7 @@ jobs:
  echo "${{ needs.benchmark-pr.outputs.result }}" > pr.bench
  echo "${{ needs.benchmark-master.outputs.result }}" > master.bench
  echo "STAT<<EOF" >> "$GITHUB_OUTPUT"
- benchstat pr.bench master.bench >> "$GITHUB_OUTPUT"
+ benchstat master.bench pr.bench >> "$GITHUB_OUTPUT"
  echo "EOF" >> "$GITHUB_OUTPUT"
  - name: Comment benchmark result
  if: ${{ !env.ACT }}