[ci] Sync test areas with test-pipeline.yaml and enable new pipeline generator (#33080)

Signed-off-by: Kevin H. Luu <khluu000@gmail.com>
Signed-off-by: khluu <khluu000@gmail.com>
Co-authored-by: Kevin Luu <khluu@Kevins-MacBook-Pro.local>

.buildkite/ci_config.yaml

@@ -1,7 +1,8 @@
 name: vllm_ci
 job_dirs:
-  - ".buildkite/test_areas"
   - ".buildkite/image_build"
+  - ".buildkite/test_areas"
+  - ".buildkite/hardware_tests"
 run_all_patterns:
   - "docker/Dockerfile"
   - "CMakeLists.txt"