Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

pkg/compiler/lib/src/inferrer/closure_tracer.dart

 // Copyright (c) 2013, 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.
 
 part of type_graph_inferrer;
 
 class ClosureTracerVisitor extends TracerVisitor<ApplyableTypeInformation> {
   final Iterable<FunctionElement> tracedElements;
   final List<CallSiteTypeInformation> callsToAnalyze =
       new List<CallSiteTypeInformation>();
@@ skipping 102 matching lines @@
 
   visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
     super.visitStaticCallSiteTypeInformation(info);
     if (info.calledElement == tracedElements.first
         && info.selector != null
         && info.selector.isGetter) {
       addNewEscapeInformation(info);
     }
   }
 }