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

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

Index: pkg/compiler/lib/src/js_backend/namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/namer.dart b/pkg/compiler/lib/src/js_backend/namer.dart
index dd5309b73d55a672d419652c269156aa1652c13d..9d86752a40b6e076b2500118701ebfc43a4ff986 100644
--- a/pkg/compiler/lib/src/js_backend/namer.dart
+++ b/pkg/compiler/lib/src/js_backend/namer.dart
@@ -1735,10 +1735,10 @@ class ConstantNamingVisitor implements ConstantValueVisitor {
   @override
   void visitConstructed(ConstructedConstantValue constant, [_]) {
     addRoot(constant.type.element.name);
-    constant.type.element.forEachInstanceField((_, FieldElement field) {
+    for (ConstantValue value in constant.fields.values) {
+      _visit(value);
       if (failed) return;
-      _visit(constant.fields[field]);
-    });
+    }
   }
 
   @override
@@ -1862,9 +1862,9 @@ class ConstantCanonicalHasher implements ConstantValueVisitor<int, Null> {
   @override
   int visitConstructed(ConstructedConstantValue constant, [_]) {
     int hash = _hashString(3, constant.type.element.name);
-    constant.type.element.forEachInstanceField((_, FieldElement field) {
-      hash = _combine(hash, _visit(constant.fields[field]));
-    });
+    for (ConstantValue value in constant.fields.values) {
+      hash = _combine(hash, _visit(value));
+    }
     return hash;
   }