Fix size of store buffer to depend on pointer size.

src/store-buffer.h

Index: src/store-buffer.h
diff --git a/src/store-buffer.h b/src/store-buffer.h
index 61b97d9e64f4a006146affdb5ca1db28bc9c299f..e5e50aeb7a8f156260e62b6ce4674a3ed8c1ae1e 100644
--- a/src/store-buffer.h
+++ b/src/store-buffer.h
@@ -81,7 +81,7 @@ class StoreBuffer {
   // surviving old-to-new pointers into the store buffer to rebuild it.
   void IteratePointersToNewSpace(ObjectSlotCallback callback);
 
-  static const int kStoreBufferOverflowBit = 1 << 16;
+  static const int kStoreBufferOverflowBit = 1 << (14 + kPointerSizeLog2);
   static const int kStoreBufferSize = kStoreBufferOverflowBit;
   static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
   static const int kOldStoreBufferLength = kStoreBufferLength * 16;