[V0 Deprecation] Remove VLLM_USE_V1 from tests (#26341)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

tests/detokenizer/test_stop_strings.py

@@ -5,7 +5,7 @@ from typing import Any, Optional
 
 import pytest
 
-from vllm import LLM, SamplingParams, envs
+from vllm import LLM, SamplingParams
 
 MODEL = "meta-llama/llama-2-7b-hf"
 MAX_TOKENS = 200
@@ -111,9 +111,7 @@ def _stop_token_id(llm):
 
 @pytest.mark.skip_global_cleanup
 def test_stop_strings():
-    # If V0, must set enforce_eager=False since we use
-    # async output processing below.
-    llm = LLM(MODEL, enforce_eager=envs.VLLM_USE_V1)
+    llm = LLM(MODEL, enforce_eager=True)
 
     _stop_basic(llm)
     _stop_multi_tokens(llm)