kernel backend impact - noSuchMethod helpers are passed a Map literal

pkg/compiler/lib/src/ssa/builder_kernel.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:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../common/codegen.dart' show CodegenRegistry, CodegenWorkItem;
 import '../common/names.dart';
@@ skipping 1906 matching lines @@
     if (constructorArgs.isEmpty) {
       constructor = astAdapter.mapLiteralConstructorEmpty;
     } else {
       constructor = astAdapter.mapLiteralConstructor;
       HLiteralList argList =
           new HLiteralList(constructorArgs, commonMasks.extendableArrayType);
       add(argList);
       inputs.add(argList);
     }
 
-    assert(constructor.kind == ir.ProcedureKind.Factory);
+    assert(constructor != null && constructor.kind == ir.ProcedureKind.Factory);
 
     ResolutionInterfaceType type = localsHandler
         .substInContext(astAdapter.getDartTypeOfMapLiteral(mapLiteral));
 
     ir.Class cls = constructor.enclosingClass;
 
     if (rtiNeed.classNeedsRti(astAdapter.getClass(cls))) {
       List<HInstruction> typeInputs = <HInstruction>[];
       type.typeArguments.forEach((ResolutionDartType argument) {
         typeInputs
@@ skipping 1483 matching lines @@
     enterBlock.setBlockFlow(
         new HTryBlockInformation(
             kernelBuilder.wrapStatementGraph(bodyGraph),
             exception,
             kernelBuilder.wrapStatementGraph(catchGraph),
             kernelBuilder.wrapStatementGraph(finallyGraph)),
         exitBlock);
     kernelBuilder.inTryStatement = previouslyInTryStatement;
   }
 }