Fix unit tests in open source environment

Summary:**Test plan**

run `npm test`, see all tests pass
Closes https://github.com/facebook/react-native/pull/6243

Differential Revision: D2999993

Pulled By: davidaurelio

fb-gh-sync-id: 54f2d5f9d28a31d132783694133df78370660421
shipit-source-id: 54f2d5f9d28a31d132783694133df78370660421

Libraries/Animated/src/Interpolation.js

@@ -12,17 +12,9 @@
 /* eslint no-bitwise: 0 */
 'use strict';
 
+var invariant = require('fbjs/lib/invariant');
 var normalizeColor = require('normalizeColor');
 
-// TODO(#7644673): fix this hack once github jest actually checks invariants
-var invariant = function(condition, message) {
-  if (!condition) {
-    var error = new Error(message);
-    (error: any).framesToPop = 1; // $FlowIssue
-    throw error;
-  }
-};
-
 type ExtrapolateType = 'extend' | 'identity' | 'clamp';
 
 export type InterpolationConfigType = {

Libraries/vendor/core/Map.js

@@ -19,7 +19,7 @@
  */
 
 var guid = require('guid');
-var isNode = require('isNode');
+var isNode = require('fbjs/lib/isNode');
 var toIterator = require('toIterator');
 var _shouldPolyfillES6Collection = require('_shouldPolyfillES6Collection');