Improve vendor chunk names in development (#9569)

Author: jrr

packages/react-scripts/config/webpack.config.js

@@ -305,7 +305,7 @@ module.exports = function (webpackEnv) {
       // https://medium.com/webpack/webpack-4-code-splitting-chunk-graph-and-the-splitchunks-optimization-be739a861366
       splitChunks: {
         chunks: 'all',
-        name: false,
+        name: isEnvDevelopment,
       },
       // Keep the runtime chunk separated to enable long term caching
       // https://twitter.com/wSokra/status/969679223278505985