[CI] Migrate JIT tests missed by #29066 to runner_config registration (#29715)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Mohammad Miadh Angkad <176301910+mmangkad@users.noreply.github.com>

test/registered/dcp/test_reduce_scatter_along_dim.py

@@ -29,7 +29,8 @@ from sglang.test.ci.ci_register import register_cuda_ci
 
 register_cuda_ci(
     est_time=120,
-    suite="base-b-kernel-unit-8-gpu-h200",
+    stage="extra-b",
+    runner_config="8-gpu-h200",
 )
 
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