refactor: consolidate is_in_ci (jit_kernel, sgl-kernel benchmarks, tests) (#21009)

sgl-kernel/benchmark/bench_per_token_group_quant_8bit.py

@@ -19,12 +19,9 @@ from sglang.srt.layers.quantization.fp8_kernel import (
 )
 from sglang.srt.utils import is_hip
 from sglang.srt.utils.bench_utils import bench_kineto
+from sglang.utils import is_in_ci
 
-# CI environment detection
-IS_CI = (
-    os.getenv("CI", "false").lower() == "true"
-    or os.getenv("GITHUB_ACTIONS", "false").lower() == "true"
-)
+IS_CI = is_in_ci()
 
 _is_hip = is_hip()
 fp8_type_ = torch.float8_e4m3fnuz if _is_hip else torch.float8_e4m3fn