Support mixins when loading from .dill

pkg/compiler/lib/src/ssa/kernel_ast_adapter.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.
 
 import 'package:js_runtime/shared/embedded_names.dart';
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../compiler.dart';
@@ skipping 161 matching lines @@
   Element getElement(ir.Node node) {
     Element result = _nodeToElement[node];
     assert(invariant(CURRENT_ELEMENT_SPANNABLE, result != null,
         message: "No element found for $node."));
     return result;
   }
 
   ConstructorElement getConstructor(ir.Member node) =>
       getElement(node).declaration;
 
+  @override
+  ConstructorEntity getSuperConstructor(
+      ir.Constructor constructor, ir.Member target) {
+    return getConstructor(target);
+  }
+
   MemberElement getMember(ir.Member node) => getElement(node).declaration;
 
   MethodElement getMethod(ir.Procedure node) => getElement(node).declaration;
 
   FieldElement getField(ir.Field node) => getElement(node).declaration;
 
   ClassElement getClass(ir.Class node) => getElement(node).declaration;
 
   LibraryElement getLibrary(ir.Library node) => getElement(node).declaration;
 
@@ skipping 631 matching lines @@
       JumpTarget continueTarget =
           astAdapter.getJumpTarget(switchCase, isContinueTarget: true);
       assert(continueTarget is KernelJumpTarget);
       targetIndexMap[continueTarget] = switchIndex;
       assert(builder.jumpTargets[continueTarget] == null);
       builder.jumpTargets[continueTarget] = this;
       switchIndex++;
     }
   }
 }