Fix latency benchmark script (#2035)

Author: WoosukKwon

benchmarks/benchmark_latency.py

@@ -72,7 +72,7 @@ def run_to_completion(profile_dir: Optional[str] = None):
     # Benchmark.
     latencies = []
     for _ in tqdm(range(args.num_iters), desc="Profiling iterations"):
-        latencies.append(run_to_completion(profile=False))
+        latencies.append(run_to_completion(profile_dir=None))
     print(f'Avg latency: {np.mean(latencies)} seconds')