[CI] Fix flaky test ...

[CI] Fix flaky test  v1/worker/test_gpu_model_runner.py::test_kv_cache_stride_order          (#24640)
Signed-off-by: Chen Zhang <zhangch99@outlook.com>

tests/v1/worker/test_gpu_model_runner.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
-import random
-
 import numpy as np
 import pytest
 import torch
@@ -409,26 +407,27 @@ def test_kv_cache_stride_order(monkeypatch, model_runner):
         model_runner.model_config.get_head_size()
     ]
     # TODO mla test
-    default_stride = list(range(5))
+    default_stride = tuple(range(5))
     # Permutation that gets you back to expected kv shape
-    rnd_stride = tuple(random.sample(default_stride, len(default_stride)))
+    for test_stride in ((1, 4, 0, 2, 3), (0, 1, 2, 3, 4)):
 
-    def rnd_stride_order():
-        return rnd_stride
+        def rnd_stride_order(test_stride=test_stride):
+            return test_stride
 
-    # Patch the attention backend class and re-trigger the KV cache creation.
+        # Patch the attention backend class and re-trigger the KV cache creation
         for attn_group in model_runner._attn_group_iterator():
             attn_backend = attn_group.backend
             monkeypatch.setattr(attn_backend, "get_kv_cache_stride_order",
                                 rnd_stride_order)
 
         model_runner.attn_groups = []
+        model_runner.kv_caches = []
         model_runner.initialize_kv_cache(model_runner.kv_cache_config)
 
         # Shape is unchanged, but layout may differ
         kv_cache_shape = model_runner.kv_caches[0].shape
         assert list(kv_cache_shape) == expected_kv_cache_shape
-    if default_stride == rnd_stride:
+        if default_stride == test_stride:
             assert all(kv.is_contiguous() for kv in model_runner.kv_caches)
         else:
             assert all(not kv.is_contiguous() for kv in model_runner.kv_caches)