Revert "Enforce use of the forEachInstanceField ordering for constructed constants."

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

 // Copyright (c) 2012, 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.
 
 part of js_backend;
 
 typedef jsAst.Expression _ConstantReferenceGenerator(ConstantValue constant);
 
 typedef jsAst.Expression _ConstantListGenerator(jsAst.Expression array);
 
@@ skipping 267 matching lines @@
         return constant.payload;
       default:
         reporter.internalError(NO_LOCATION_SPANNABLE,
             "Unexpected DummyConstantKind ${constant.kind}");
         return null;
     }
   }
 
   @override
   jsAst.Expression visitConstructed(ConstructedConstantValue constant, [_]) {
-    ClassElement element = constant.type.element;
+    Element element = constant.type.element;
     if (backend.isForeign(element) && element.name == 'JS_CONST') {
       StringConstantValue str = constant.fields.values.single;
       String value = str.primitiveValue.slowToString();
       return new jsAst.LiteralExpression(stripComments(value));
     }
     jsAst.Expression constructor =
         backend.emitter.constructorAccess(constant.type.element);
-    List<jsAst.Expression> fields = <jsAst.Expression>[];
-    element.forEachInstanceField((_, FieldElement field) {
-      fields.add(constantReferenceGenerator(constant.fields[field]));
-    });
+    List<jsAst.Expression> fields = constant.fields.values
+        .map(constantReferenceGenerator)
+        .toList(growable: false);
     jsAst.New instantiation = new jsAst.New(constructor, fields);
     return maybeAddTypeArguments(constant.type, instantiation);
   }
 
   String stripComments(String rawJavaScript) {
     return rawJavaScript.replaceAll(COMMENT_RE, '');
   }
 
   jsAst.Expression maybeAddTypeArguments(
       InterfaceType type, jsAst.Expression value) {
@@ skipping 12 matching lines @@
           [value, argumentList]);
     }
     return value;
   }
 
   @override
   jsAst.Expression visitDeferred(DeferredConstantValue constant, [_]) {
     return constantReferenceGenerator(constant.referenced);
   }
 }