test_urls: Summarize the broken URLs at the end

Spotting the `FAIL` entry in literally thousands of entries is quite
inconvenient, so list the broken URLs again before exiting.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

scripts/test_urls.py

@@ -109,9 +109,8 @@ for url in urls:
         broken.append(url)
     print(url, "OK" if status else "FAIL", f"{end - start:0.4f}s")
 
-print(f"Found {len(broken)} broken URLs in {len(urls)} tested")
+print(f"Found {len(broken)} broken URLs in {len(urls)} tested:")
+for b in broken:
+    print(" ", b)
 
-if broken:
-    sys.exit(1)
-
-sys.exit(0)
+sys.exit(1 if broken else 0)