Cleanup the transformer flow types

Summary:
Since the options that are passed to the `babelTransformer` are not exactly the same ones as the `transformer` receives, we need to have a specific object for them.

This allows us to make the transformer options object strict (since unfortunately the `babeltransformer` options object comes from many places and needs a bit of work to be able to be strict...

Reviewed By: mjesun

Differential Revision: D9309173

fbshipit-source-id: 0a92381968f17e5eb6c4740c1ca89580fa7ee4d3

jest/preprocessor.js

@@ -53,6 +53,8 @@ module.exports = {
         ast: true, // needed for open source (?) https://github.com/facebook/react-native/commit/f8d6b97140cffe8d18b2558f94570c8d1b410d5c#r28647044
         dev: true,
         disableBabelRuntime: true,
+        experimentalImportSupport: false,
+        hot: false,
         inlineRequires: true,
         minify: false,
         platform: '',