fix(compiler-core): handle template root and template v-if as stable fragments

jest.config.js

@@ -5,6 +5,7 @@ module.exports = {
     __TEST__: true,
     __VERSION__: require('./package.json').version,
     __BROWSER__: false,
+    __BUNDLER__: false,
     __RUNTIME_COMPILE__: true,
     __FEATURE_OPTIONS__: true,
     __FEATURE_SUSPENSE__: true