Tweak syntax in rollup build script (#9852)

* Tweak syntax in rollup build script

@bvaughn and I already discussed this.

**test plan:**
`yarn build`

* Remove JSDoc comments

**what is the change?:**
removing some comments

**why make this change?:**
The code is basically self explanatory and these comments could get out
of sync.

**test plan:**
Visual inspection, `yarn build` and `yarn test`

**issue:**
#9398

scripts/rollup/build.js

@@ -194,13 +194,12 @@ function getFilename(name, hasteName, bundleType) {
   }
 }
 
-function uglifyConfig({
-  mangle,
-  manglePropertiesOnProd,
-  preserveVersionHeader,
-  removeComments,
-  headerSanityCheck,
-}) {
+function uglifyConfig(configs) {
+  var mangle = configs.mangle;
+  var manglePropertiesOnProd = configs.manglePropertiesOnProd;
+  var preserveVersionHeader = configs.preserveVersionHeader;
+  var removeComments = configs.removeComments;
+  var headerSanityCheck = configs.headerSanityCheck;
   return {
     warnings: false,
     compress: {