Remove prod build of jest-react

This honestly shouldn't be a public package anyway. We thought it might
be at one point but it's not, despite the fact that it gets published.
It's really only used by our repo, as a place to put our internal test
helpers. It might as well just live in scripts/ or something.

We don't need a prod build of it. My immediate motivation is so I can
use async/await in the new helpers I'm implementing.

packages/jest-react/npm/index.js

@@ -1,7 +1,3 @@
 'use strict';
 
-if (process.env.NODE_ENV === 'production') {
-  module.exports = require('./cjs/jest-react.production.min.js');
-} else {
-  module.exports = require('./cjs/jest-react.development.js');
-}
+module.exports = require('./cjs/jest-react.development.js');

scripts/rollup/bundles.js

@@ -954,7 +954,7 @@ const bundles = [
 
   /******* Jest React (experimental) *******/
   {
-    bundleTypes: [NODE_DEV, NODE_PROD],
+    bundleTypes: [NODE_DEV],
     moduleType: ISOMORPHIC,
     entry: 'jest-react',
     global: 'JestReact',