[KVCache] Make KVCacheSpec hashable (#21791)

Signed-off-by: Chen Zhang <zhangch99@outlook.com>

tests/v1/e2e/test_correctness_sliding_window.py

@@ -30,7 +30,9 @@ model_config = {
     ])
 @pytest.mark.parametrize("batch_size", [5])
 @pytest.mark.parametrize("seed", [1])
-def test_sliding_window_retrieval(monkeypatch, model, batch_size, seed):
+@pytest.mark.parametrize("disable_hybrid_kv_cache_manager", [True, False])
+def test_sliding_window_retrieval(monkeypatch, model, batch_size, seed,
+                                  disable_hybrid_kv_cache_manager):
     """
     The test does a bunch of assignments "x1 = 10\nx2 = 33\n..." and then
     asks for value of one of them (which is outside the sliding window).
@@ -42,7 +44,9 @@ def test_sliding_window_retrieval(monkeypatch, model, batch_size, seed):
 
         test_config = model_config[model]
 
-        llm = LLM(model=model)
+        llm = LLM(
+            model=model,
+            disable_hybrid_kv_cache_manager=disable_hybrid_kv_cache_manager)
         sampling_params = SamplingParams(temperature=0.0, max_tokens=100)
 
         prompts, answer, indices = prep_prompts(batch_size,