vLLM Benchmark Suite perf regression after PR#32723 (#38576)

Signed-off-by: louie-tsai <louie.tsai@intel.com>

.buildkite/performance-benchmarks/tests/serving-tests-arm64-cpu.json

@@ -36,6 +36,7 @@
       "model": "meta-llama/Llama-3.1-8B-Instruct",
       "backend": "vllm",
       "ignore-eos": "",
+      "temperature": 0,
       "num_prompts": 200
     }
   },
@@ -127,4 +128,4 @@
       }
     }
   ]
-}
+}