Split the Kernel transformations into modular and global ones

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);
+  void performGlobalTransformations(Program program) {
+    super.performGlobalTransformations(program);
     cc.transformProgram(program);
   }
 }