Delete repeated tests (#5740)

frameworks/PHP/comet/benchmark_config.json

@@ -25,8 +25,6 @@
       "versus": "php"
     },
     "mysql": {
-      "json_url": "/json",
-      "plaintext_url": "/plaintext",
       "db_url": "/db",
       "query_url": "/query?q=",
       "update_url": "/update?q=",