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

.claude/skills/add-sgl-kernel/SKILL.md

@@ -244,18 +244,15 @@ Create `sgl-kernel/benchmark/bench_scale.py`:
 
 ```python
 import itertools
-import os
 
 import torch
 import triton
 import triton.testing
 
 import sgl_kernel
+from sglang.utils import is_in_ci
 
-IS_CI = (
-    os.getenv("CI", "false").lower() == "true"
-    or os.getenv("GITHUB_ACTIONS", "false").lower() == "true"
-)
+IS_CI = is_in_ci()
 
 dtypes  = [torch.float16] if IS_CI else [torch.float16, torch.bfloat16, torch.float32]
 sizes   = [4096] if IS_CI else [2**n for n in range(10, 20)]  # 1K … 512K