[Refactor] Use is_in_ci() utility in JIT kernel benchmarks (#17118)

python/sglang/jit_kernel/benchmark/bench_qknorm.py

@@ -1,5 +1,4 @@
 import itertools
-import os
 from typing import Tuple
 
 import torch
@@ -7,13 +6,11 @@ import triton
 import triton.testing
 from sgl_kernel import rmsnorm
 
+from sglang.jit_kernel.benchmark.utils import is_in_ci
 from sglang.jit_kernel.norm import fused_inplace_qknorm
 from sglang.srt.utils import get_current_device_stream_fast
 
-IS_CI = (
-    os.getenv("CI", "false").lower() == "true"
-    or os.getenv("GITHUB_ACTIONS", "false").lower() == "true"
-)
+IS_CI = is_in_ci()
 
 alt_stream = torch.cuda.Stream()