Fix type masks for js-interop types.

pkg/compiler/lib/src/js_backend/backend.dart

Index: pkg/compiler/lib/src/js_backend/backend.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend.dart b/pkg/compiler/lib/src/js_backend/backend.dart
index d155aaa35c255c36096b0a10bbf36e906f059b28..2bd492d656ede023310ad8c0eaf8463963d25dcb 100644
--- a/pkg/compiler/lib/src/js_backend/backend.dart
+++ b/pkg/compiler/lib/src/js_backend/backend.dart
@@ -635,6 +635,11 @@ class JavaScriptBackend extends Backend {
   JavaScriptConstantCompiler get constants {
     return constantCompilerTask.jsConstantCompiler;
   }
+  
+  @override
+  bool isDefaultNoSuchMethod(MethodElement element) {
+    return noSuchMethodRegistry.isDefaultNoSuchMethodImplementation(element);
+  }
 
   MethodElement resolveExternalFunction(MethodElement element) {
     if (isForeign(element)) {