message: avoid externals warning in ssr tests
diff: @@ -25,6 +25,7 @@ function createRenderer (file, cb, options) {
  module: {
  rules: [{ test: /\.js$/, loader: 'babel-loader' }]
  },
  + externals: [require.resolve('../../dist/vue.runtime.common.js')],
  plugins: asBundle
  ? [new VueSSRPlugin()]
  : []
  