[heap] Remove store buffer top from roots

src/snapshot/startup-serializer.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/snapshot/startup-serializer.h"
 
 #include "src/objects-inl.h"
 #include "src/v8threads.h"
 
 namespace v8 {
@@ skipping 132 matching lines @@
         skip = 0;
       }
     }
     FlushSkip(skip);
   } else {
     Serializer::VisitPointers(start, end);
   }
 }
 
 bool StartupSerializer::RootShouldBeSkipped(int root_index) {
-  if (root_index == Heap::kStoreBufferTopRootIndex ||
-      root_index == Heap::kStackLimitRootIndex ||
+  if (root_index == Heap::kStackLimitRootIndex ||
       root_index == Heap::kRealStackLimitRootIndex) {
     return true;
   }
   return Heap::RootIsImmortalImmovable(root_index) !=
          serializing_immortal_immovables_roots_;
 }
 
 }  // namespace internal
 }  // namespace v8