Added stack renderer to react-test-renderer bundle temporarily (#9514)

Also fixed an error in a temporary export property that had been added to the React object

Author: bvaughn

package.json

@@ -27,6 +27,7 @@
     "README.md",
     "index.js",
     "shallow.js",
+    "stack.js",
     "cjs/"
   ]
 }

stack.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+  throw Error('test renderer is not available in production mode.');
+} else {
+  module.exports = require('./cjs/react-test-renderer-stack.development');
+}