Make babel-standalone an ESModule and enable flow (#9025)

* Make babel-standalone an ESModule and enable flow

* autogenerate plugin list

* Make config an array

scripts/utils/writeFileAndMkDir.js

@@ -0,0 +1,14 @@
+const fs = require("fs");
+const path = require("path");
+
+module.exports = function writeFileAndMkDir(file, content) {
+  try {
+    fs.mkdirSync(path.dirname(file));
+  } catch (error) {
+    if (error.code !== "EEXIST") {
+      throw error;
+    }
+  }
+
+  fs.writeFileSync(file, content);
+};