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

src/heap/heap-inl.h

Index: src/heap/heap-inl.h
diff --git a/src/heap/heap-inl.h b/src/heap/heap-inl.h
index 6048d3e5256dc5ad02e52ac85033ac551c282639..e81829c38d01892bf6f9390b72b47fa20e3a33d5 100644
--- a/src/heap/heap-inl.h
+++ b/src/heap/heap-inl.h
@@ -27,13 +27,6 @@ void PromotionQueue::insert(HeapObject* target, int 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));