Update expectations.

pkg/front_end/testcases/rasta/duplicated_mixin.dart.direct.expect

Index: pkg/front_end/testcases/rasta/duplicated_mixin.dart.direct.expect
diff --git a/pkg/front_end/testcases/rasta/duplicated_mixin.dart.direct.expect b/pkg/front_end/testcases/rasta/duplicated_mixin.dart.direct.expect
index 56b7784172b31abf46129270ecfe5d537f782d46..5ed76f83ff435c4a2f571498bd47498867ea403e 100644
--- a/pkg/front_end/testcases/rasta/duplicated_mixin.dart.direct.expect
+++ b/pkg/front_end/testcases/rasta/duplicated_mixin.dart.direct.expect
@@ -8,20 +8,12 @@ class Mixin extends core::Object {
     : super core::Object::•()
     ;
 }
-abstract class Object&Mixin extends core::Object implements self::Mixin {
-  field dynamic field = null;
-  constructor •() → void
-    : super core::Object::•()
-    ;
+abstract class Object&Mixin = core::Object with self::Mixin {
 }
-abstract class Object&Mixin&Mixin extends self::Object&Mixin implements self::Mixin {
-  field dynamic field = null;
-  constructor •() → void
-    : super self::Object&Mixin::•()
-    ;
+abstract class Object&Mixin&Mixin = self::Object&Mixin with self::Mixin {
 }
 class A extends self::Object&Mixin&Mixin {
   default constructor •() → void
-    : super self::Object&Mixin&Mixin::•()
+    : super core::Object::•()
     ;
 }