Add regression.out cat

Author: tuhaihe

.github/workflows/build-cloudberry-rocky8.yml

@@ -1520,6 +1520,18 @@ jobs:
 
           exit $overall_status
 
+      - name: Check and Display Regression Diffs
+        if: always()
+        run: |
+          # Search for regression.diffs recursively
+          found_file=$(find . -type f -name "regression.diffs" | head -n 1)
+          if [[ -n "$found_file" ]]; then
+            echo "Found regression.diffs at: $found_file"
+            cat "$found_file"
+          else
+            echo "No regression.diffs file found in the hierarchy."
+          fi
+
       - name: "Check for core dumps: ${{ matrix.test }}"
         id: check-cores
         if: always()