test(WebPlatform): disable web components tests on IE

ref dart-archive#1300

Author: vicb

test/core_dom/web_platform_spec.dart

@@ -1,10 +1,14 @@
 library angular.dom.platform_spec;
 
 import '../_specs.dart';
+import 'package:browser_detect/browser_detect.dart';
 
 import 'dart:js' as js;
 
 main() {
+  // TODO(vicb) WebPlatform does not work with polyfills
+  // see https://github.com/angular/angular.dart/issues/1300
+  if (browser.isIe) return;
   describe('WebPlatform', () {
 
     beforeEachModule((Module module) {