[heap] Remove store buffer top from roots

src/heap/heap.cc

 // Copyright 2012 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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 2916 matching lines @@
   // Initialize descriptor cache.
   isolate_->descriptor_lookup_cache()->Clear();
 
   // Initialize compilation cache.
   isolate_->compilation_cache()->Clear();
 }
 
 
 bool Heap::RootCanBeWrittenAfterInitialization(Heap::RootListIndex root_index) {
   switch (root_index) {
-    case kStoreBufferTopRootIndex:
     case kNumberStringCacheRootIndex:
     case kInstanceofCacheFunctionRootIndex:
     case kInstanceofCacheMapRootIndex:
     case kInstanceofCacheAnswerRootIndex:
     case kCodeStubsRootIndex:
     case kNonMonomorphicCacheRootIndex:
     case kPolymorphicCodeCacheRootIndex:
     case kEmptyScriptRootIndex:
     case kSymbolRegistryRootIndex:
     case kScriptListRootIndex:
@@ skipping 3524 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8