Add retry for flaky tests in CI (#4755)

test/srt/models/test_grok_models.py

@@ -6,11 +6,12 @@ from sglang.test.few_shot_gsm8k import run_eval
 from sglang.test.test_utils import (
     DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
     DEFAULT_URL_FOR_TEST,
+    CustomTestCase,
     popen_launch_server,
 )
 
 
-class TestGrok(unittest.TestCase):
+class TestGrok(CustomTestCase):
     @classmethod
     def setUpClass(cls):
         cls.model = "lmzheng/grok-1"