Use just one to-space page for the promotion queue.

src/heap/heap-inl.h

 // 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.
 
 #ifndef V8_HEAP_HEAP_INL_H_
 #define V8_HEAP_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/base/platform/platform.h"
 #include "src/cpu-profiler.h"
 #include "src/heap/heap.h"
 #include "src/heap/store-buffer.h"
 #include "src/heap/store-buffer-inl.h"
 #include "src/heap-profiler.h"
 #include "src/isolate.h"
 #include "src/list-inl.h"
 #include "src/msan.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 void PromotionQueue::insert(HeapObject* target, int size) {
   if (emergency_stack_ != NULL) {
     emergency_stack_->Add(Entry(target, size));
     return;
   }
 
-  if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(rear_))) {
-    NewSpacePage* rear_page =
-        NewSpacePage::FromAddress(reinterpret_cast<Address>(rear_));
-    DCHECK(!rear_page->prev_page()->is_anchor());
-    rear_ = reinterpret_cast<intptr_t*>(rear_page->prev_page()->area_end());
-  }
-
   if ((rear_ - 2) < limit_) {
     RelocateQueueHead();
     emergency_stack_->Add(Entry(target, size));
     return;
   }
 
   *(--rear_) = reinterpret_cast<intptr_t>(target);
   *(--rear_) = size;
 // Assert no overflow into live objects.
 #ifdef DEBUG
@@ skipping 708 matching lines @@
 
 void VerifySmisVisitor::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     CHECK((*current)->IsSmi());
   }
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_INL_H_