Implement constructor bodies and initializers in CPS->JS backend.

pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart

Index: pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
diff --git a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
index 7adc39fb50501a0f44d5d99112d8f3f2aebcd573..01a9ae0869e91d4bcf6a753ea9d3e2ff6186e991 100644
--- a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
@@ -909,7 +909,7 @@ class ASTEmitter
   visitCreateBox(tree.CreateBox node, arg) => errorUnsupportedNode(node);
 
   @override
-  visitCreateClosureClass(tree.CreateClosureClass node, arg) {
+  visitCreateInstance(tree.CreateInstance node, arg) {
     return errorUnsupportedNode(node);
   }