[CI] Migrate e2e test runner to hk (#5344)

### What this PR does / why we need it?
This patch add new runner labels for the HK region, and e2e single-card
testing has been migrated to this runner.

- vLLM version: release/v0.13.0
- vLLM main:
bc0a5a0c08

---------

Signed-off-by: wangli <wangli858794774@gmail.com>

.github/workflows/_e2e_test.yaml

@@ -22,7 +22,7 @@ on:
 jobs:
   e2e:
     name: singlecard
-    runs-on: ${{ inputs.runner }}-1
+    runs-on: linux-aarch64-a2b3-1
     container:
       image: ${{ inputs.image }}
       env:
@@ -425,4 +425,4 @@ jobs:
           PYTORCH_NPU_ALLOC_CONF: max_split_size_mb:256
           VLLM_WORKER_MULTIPROC_METHOD: spawn
         run: |
-          pytest -sv --durations=0 tests/e2e/310p/test_offline_inference_parallel_310p.py
+          pytest -sv --durations=0 tests/e2e/310p/test_offline_inference_parallel_310p.py