[ci] fix model tests (vllm-project#7507)

Author: youkaichao

.buildkite/test-pipeline.yaml

@@ -159,7 +159,8 @@ steps:
   - tests/models
   commands:
     - pip install -e ./plugins/vllm_add_dummy_model
-    - pytest -v -s models -m \"not vlm\"
+    - pytest -v -s models/test_oot_registration.py # it needs a clean process
+    - pytest -v -s models -m \"not vlm\" --ignore=models/test_oot_registration.py
 
 - label: Vision Language Models Test # 42min
   mirror_hardwares: [amd]