fix(facades): fix splice semantics; add test

modules/angular2/test/facade/collection_spec.js

@@ -0,0 +1,16 @@
+import {describe, it, expect, beforeEach, ddescribe, iit, xit}
+  from 'angular2/test_lib';
+
+import {List, ListWrapper} from 'angular2/src/facade/collection';
+
+export function main() {
+  describe('ListWrapper', () => {
+    describe('splice', () => {
+      it('should remove sublist of given length and return it',  () => {
+        var list = [1, 2, 3, 4, 5, 6];
+        expect(ListWrapper.splice(list, 1, 3)).toEqual([2, 3, 4]);
+        expect(list).toEqual([1, 5, 6]);
+      });
+    });
+ });
+}