misc: yarn static-server (#9293)

package.json

@@ -61,7 +61,8 @@
     "mixed-content": "./lighthouse-cli/index.js --chrome-flags='--headless' --preset=mixed-content",
     "minify-latest-run": "./lighthouse-core/scripts/lantern/minify-trace.js ./latest-run/defaultPass.trace.json ./latest-run/defaultPass.trace.min.json && ./lighthouse-core/scripts/lantern/minify-devtoolslog.js ./latest-run/defaultPass.devtoolslog.json ./latest-run/defaultPass.devtoolslog.min.json",
     "compile-proto": "protoc --python_out=./ ./proto/lighthouse-result.proto && mv ./proto/*_pb2.py ./proto/scripts || (echo \"❌ Install protobuf ≥ 3.7.1 to compile the proto file.\" && false)",
-    "build-proto-roundtrip": "cd proto/scripts && PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=2 python json_roundtrip_via_proto.py"
+    "build-proto-roundtrip": "cd proto/scripts && PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=2 python json_roundtrip_via_proto.py",
+    "static-server": "node lighthouse-cli/test/fixtures/static-server.js"
   },
   "devDependencies": {
     "@firebase/app-types": "0.3.1",