fix #29753, use ES5 constructors for ddc

pkg/dev_compiler/tool/input_sdk/private/js_mirrors.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart._js_mirrors;
 
 import 'dart:mirrors';
 import 'dart:_foreign_helper' show JS;
 import 'dart:_internal' as _internal;
 
@@ skipping 424 matching lines @@
       _typeArguments =
           new List.unmodifiable(typeArgs.map((t) => reflectType(_wrap(t))));
     }
   }
 
   InstanceMirror newInstance(Symbol constructorName, List args,
       [Map<Symbol, dynamic> namedArgs]) {
     // TODO(vsm): Support factory constructors and named arguments.
     var name = getName(constructorName);
     assert(namedArgs == null || namedArgs.isEmpty);
-    var instance = (name == 'new' || name == '')
-        ? JS('', 'new #(...#)', _unwrap(_cls), args)
-        : JS('', 'new (#.#)(...#)', _unwrap(_cls), name, args);
+    if (name == '') name = 'new';
+    var instance = JS('', 'new (#.#)(...#)', _unwrap(_cls), name, args);
     return reflect(instance);
   }
 
   // TODO(vsm): Need to check for NSM, types on accessors below.  Unlike the
   // InstanceMirror case, there is no dynamic helper to delegate to - we never
   // need a dload, etc. on a static.
 
   InstanceMirror getField(Symbol symbol) {
     var name = getName(symbol);
     return reflect(JS('', '#[#]', _unwrap(_cls), name));
@@ skipping 201 matching lines @@
       var param =
           new JsParameterMirror._(new Symbol(''), _wrap(type), metadata);
       params[i + args.length] = param;
     }
 
     _params = new List.unmodifiable(params);
   }
 
   String toString() => "MethodMirror on '$_name'";
 }