Support mixin application equivalence in impact_test.

tests/compiler/dart2js/kernel/impact_test.dart

 // Copyright (c) 2016, 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 dart2js.kernel.impact_test;
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/common/names.dart';
@@ skipping 166 matching lines @@
   testForwardingConstructorGeneric();
   testEnum();
   testStaticGenericMethod();
   testInstanceGenericMethod();
   testDynamicPrivateMethodInvoke();
   testJSCall();
   testNativeMethod();
   testNativeMethodCreates();
   testNativeMethodReturns();
   testNativeField(null);
+  testMixinInstantiation();
+  testNamedMixinInstantiation();
 }
 
 testEmpty() {}
 testNull() => null;
 testTrue() => true;
 testFalse() => false;
 testInt() => 42;
 testDouble() => 37.5;
 testString() => 'foo';
 testStringInterpolation() => '${0}';
@@ skipping 422 matching lines @@
 testNativeMethodReturns() native;
 
 @Native("NativeClass")
 class NativeClass {
   @annotation_Creates_SerializedScriptValue
   final Object field;
 
   factory NativeClass._() { throw new UnsupportedError("Not supported"); }
 }
 testNativeField(NativeClass c) => c.field;
+testMixinInstantiation() => new Sub();
+testNamedMixinInstantiation() => new NamedMixin();
 ''',
   'sdk/tests/compiler/dart2js_native/helper.dart': '''
 import 'dart:_js_helper';
 class Class {
   const Class.generative();
   factory Class.fact() => null;
   const factory Class.redirect() = Class.generative;
 }
 class GenericClass<X, Y> {
   const GenericClass.generative();
   factory GenericClass.fact() => null;
   const factory GenericClass.redirect() = GenericClass<X, Y>.generative;
 
   Map<X, T> genericMethod<T>(T arg) => { null: arg };
 }
 typedef Typedef();
 typedef X GenericTypedef<X, Y>(Y y);
 
+class Super {}
+class Mixin1 {}
+class Mixin2 {}
+class Sub extends Super with Mixin1, Mixin2 {}
+class NamedMixin = Super with Mixin1, Mixin2;
+
 const String _serializedScriptValue =
     'num|String|bool|'
     'JSExtendableArray|=Object';
 const annotation_Creates_SerializedScriptValue =
     const Creates(_serializedScriptValue);''',
 };
 
 main(List<String> args) {
   bool fullTest = args.contains('--full');
   asyncTest(() async {
@@ skipping 207 matching lines @@
         visitList(type.optionalParameterTypes),
         type.namedParameters,
         visitList(type.namedParameterTypes));
   }
 }
 
 /// Perform unaliasing of all typedefs nested within a [ResolutionDartType].
 ResolutionDartType unalias(ResolutionDartType type) {
   return const Unaliaser().visit(type);
 }