Add VM target with closure conversion to dartk

pkg/kernel/lib/target/vmcc.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 kernel.target.vmcc;
+
+import '../ast.dart' show Program;
+import '../transformations/closure_conversion.dart' as cc show transformProgram;
+
+import 'targets.dart' show TargetFlags;
+import 'vm.dart' as vm_target;
+
+class VmClosureConvertedTarget extends vm_target.VmTarget {
+  VmClosureConvertedTarget(TargetFlags flags) : super(flags);
+
+  @override
+  String get name => "vmcc";
+
+  @override
+  void transformProgram(Program program) {
+    super.transformProgram(program);
+    cc.transformProgram(program);
+  }
+}