checker: disallow top level decl builtin fn (#17857)

.github/workflows/v_benchmark_ci.yml

@@ -1,36 +0,0 @@
-name: vlang benchmarks
-
-on:
-  push:
-    paths-ignore:
-      - "**.md"
-  pull_request:
-    paths-ignore:
-      - "**.md"
-
-jobs:
-  run:
-    name: Run
-    runs-on: ubuntu-latest
-    if: github.event_name != 'push' || github.event.ref == 'refs/heads/master' || github.event.repository.full_name != 'vlang/v'
-    steps:
-    - name: Checkout
-      uses: actions/checkout@v3
-    - name: Install google benchmark
-      run: |
-          git clone https://github.com/google/benchmark.git
-          cd benchmark
-          cmake -E make_directory "build"
-          cmake -E chdir "build" cmake -DBENCHMARK_DOWNLOAD_DEPENDENCIES=on -DCMAKE_BUILD_TYPE=Release ../
-          sudo cmake --build "build" --config Release --target install
-    - name: Run V benchmark
-      run: |
-        make
-        sudo ./v symlink
-        git clone https://github.com/vincenzopalazzo/benchmarks.git
-        cd benchmarks
-        make vdep && make v
-    - uses: actions/upload-artifact@v3
-      with:
-        name: vlang-benchmark
-        path: benchmarks/vlang/*.json