feat(plugin-legacy): use compact output when transpiling legacy chunks

close #1828

Author: yyx990803

packages/plugin-legacy/index.js

@@ -204,6 +204,7 @@ function viteLegacyPlugin(options = {}) {
       let { code, ast, map } = loadBabel().transform(raw, {
         ast: true,
         configFile: false,
+        compact: true,
         sourceMaps,
         inputSourceMap: sourceMaps && chunk.map,
         presets: [