Return an empty object when failing to determine global scope.

papaparse.js

@@ -35,7 +35,8 @@
 		if (typeof window !== 'undefined') { return window; }
 		if (typeof global !== 'undefined') { return global; }
 
-		throw new Error('Cannot determine global object');
+        // When running tests none of the above have been defined
+        return {};
 	})();