[Bug] Fix torch dynamo warning Dynamo detected a call to a functools.lru_cache (#29038)

Signed-off-by: yewentao256 <zhyanwentao@126.com>

tests/v1/determinism/conftest.py

@@ -1,11 +1,12 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-
 import pytest
 
+import vllm.model_executor.layers.batch_invariant as batch_invariant
+
 
 @pytest.fixture(autouse=True)
 def enable_batch_invariant_mode(monkeypatch: pytest.MonkeyPatch):
     """Automatically enable batch invariant kernel overrides for all tests."""
+    monkeypatch.setattr(batch_invariant, "VLLM_BATCH_INVARIANT", True)
     monkeypatch.setenv("VLLM_BATCH_INVARIANT", "1")
-    yield