[CI] Migrate Attention Backend tests to test/registered/attention/ (#15563)

.github/workflows/pr-test.yml

@@ -522,6 +522,43 @@ jobs:
           cd test/
           python3 run_suite.py --hw cuda --suite stage-b-test-large-2-gpu
 
+  stage-c-test-large-4-gpu:
+    needs: [check-changes, call-gate, stage-b-test-small-1-gpu, stage-b-test-large-1-gpu, stage-b-test-large-2-gpu, sgl-kernel-build-wheels]
+    if: |
+      always() &&
+      (
+        (inputs.target_stage == 'stage-c-test-large-4-gpu') ||
+        (
+          !inputs.target_stage &&
+          (github.event_name == 'schedule' || (!failure() && !cancelled())) &&
+          ((needs.check-changes.outputs.main_package == 'true') || (needs.check-changes.outputs.sgl_kernel == 'true'))
+        )
+      )
+    runs-on: 4-gpu-h100
+    env:
+      RUNNER_LABELS: 4-gpu-h100
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Download artifacts
+        if: needs.check-changes.outputs.sgl_kernel == 'true'
+        uses: actions/download-artifact@v4
+        with:
+          path: sgl-kernel/dist/
+          merge-multiple: true
+          pattern: wheel-python3.10-cuda12.9
+
+      - name: Install dependencies
+        run: |
+          CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} bash scripts/ci/ci_install_dependency.sh
+
+      - name: Run test
+        timeout-minutes: 30
+        run: |
+          cd test/
+          python3 run_suite.py --hw cuda --suite stage-c-test-large-4-gpu
+
   multimodal-gen-test-1-gpu:
     needs: [check-changes, call-gate, sgl-kernel-build-wheels]
     if: |
@@ -1402,6 +1439,7 @@ jobs:
         stage-b-test-small-1-gpu,
         stage-b-test-large-1-gpu,
         stage-b-test-large-2-gpu,
+        stage-c-test-large-4-gpu,
         quantization-test,
         unit-test-backend-1-gpu,
         unit-test-backend-2-gpu,