[CI] Add wait logic for each individual case (#6036)

### What this PR does / why we need it?
Wait until the NPU memory is clean
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: v0.13.0
- vLLM main:
2c24bc6996

---------

Signed-off-by: wangli <wangli858794774@gmail.com>
Signed-off-by: leo-pony <nengjunma@outlook.com>
Co-authored-by: leo-pony <nengjunma@outlook.com>

tests/e2e/multicard/4-cards/long_sequence/test_basic.py

@@ -20,7 +20,7 @@ import os
 
 from vllm import SamplingParams
 
-from tests.e2e.conftest import VllmRunner
+from tests.e2e.conftest import VllmRunner, wait_until_npu_memory_free
 
 os.environ["HCCL_BUFFSIZE"] = "768"
 
@@ -126,6 +126,7 @@ def test_models_pcp_dcp_piece_wise():
         runner.model.generate(prompts, sampling_params)
 
 
+@wait_until_npu_memory_free()
 def test_pcp_basic():
     prompts = [
         "The capital of France is", "Hello, my name is Tom, I am",