Reclaim the CreatedFromSnapshot bit and use it to indicate VM Heap object

runtime/vm/dart_api_message.cc

Index: runtime/vm/dart_api_message.cc
diff --git a/runtime/vm/dart_api_message.cc b/runtime/vm/dart_api_message.cc
index 2788be09d8df98f66c205ebb39e2435d96b3e1f7..69fb8919b44a160b31f143fac915f42834c0f913 100644
--- a/runtime/vm/dart_api_message.cc
+++ b/runtime/vm/dart_api_message.cc
@@ -535,6 +535,7 @@ Dart_CObject* ApiMessageReader::ReadInternalVMObject(intptr_t class_id,
                                                      intptr_t object_id) {
   switch (class_id) {
     case kClassCid: {
+      Read<bool>();  // Consume the is_in_fullsnapshot indicator.
       Dart_CObject_Internal* object = AllocateDartCObjectClass();
       AddBackRef(object_id, object, kIsDeserialized);
       object->internal.as_class.library_url = ReadObjectImpl();