Properly expose TestUtils through top-level package (#3086)

src/TestUtils.js

@@ -1,7 +1,7 @@
 import AppCache from './cache';
 
 //Used by tests
-function destroyAllDataPermanently() {
+export function destroyAllDataPermanently() {
   if (!process.env.TESTING) {
     throw 'Only supported in test environment';
   }
@@ -14,7 +14,3 @@ function destroyAllDataPermanently() {
       }
     }));
 }
-
-export {
-  destroyAllDataPermanently
-}