speedup pr test for sgl-kernel (#3126)

.github/workflows/pr-test-sgl-kernel.yml

@@ -30,20 +30,55 @@ jobs:
           clangFormatVersion: 16
           style: file
 
+  build-wheels:
+    if: github.repository == 'sgl-project/sglang'
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.10']
+        cuda-version: ['12.4']
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: 'recursive'
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Build wheels for Python ${{ matrix.python-version }} and CUDA ${{ matrix.cuda-version }}
+        run: |
+          cd sgl-kernel
+          chmod +x ./build.sh
+          ./build.sh "${{ matrix.python-version }}" "${{ matrix.cuda-version }}"
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheel-python${{ matrix.python-version }}-cuda${{ matrix.cuda-version }}
+          path: sgl-kernel/dist/*
+
   unit-test:
     if: github.repository == 'sgl-project/sglang' || github.event_name == 'pull_request'
+    needs: build-wheels
     runs-on: 1-gpu-runner
     steps:
       - uses: actions/checkout@v4
 
+      - name: Download artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: sgl-kernel/dist/
+          merge-multiple: true
+          pattern: wheel-*
+
       - name: Install
         run: |
           pip3 install torch==2.5.1 && pip3 install pytest && pip3 install vllm==0.6.4.post1
           pip3 uninstall sgl-kernel -y || true
-          find . -name index.lock -delete
-          cd sgl-kernel
-          git submodule deinit --all --force && git submodule sync --recursive && git submodule update --init --force --recursive
-          pip3 install .
+          pip3 install sgl-kernel/dist/*whl --force-reinstall --no-deps
           pip3 list | grep sgl-kernel
 
       - name: Run test