VM: Support bootstrapping core libraries from Kernel binaries instead of source.

runtime/vm/kernel.cc

 // 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.
 
 #include "vm/kernel.h"
 
+#if !defined(DART_PRECOMPILED_RUNTIME)
 namespace dart {
 
 namespace kernel {
 
 
 template <typename T>
 void VisitList(List<T>* list, Visitor* visitor) {
   for (int i = 0; i < list->length(); ++i) {
     (*list)[i]->AcceptVisitor(visitor);
   }
@@ skipping 1183 matching lines @@
 
 void Program::VisitChildren(Visitor* visitor) {
   VisitList(&libraries(), visitor);
   visitor->VisitProcedureReference(main_method());
 }
 
 
 }  // namespace kernel
 
 }  // namespace dart
+#endif  // !defined(DART_PRECOMPILED_RUNTIME)