Revert of Replace slots buffer with remembered set.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 88310422b4eba65f168d9065895ed4fe0302912e..f7283fa1ce2810a752abfd5ec56dbdffa9f21aef 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -5574,7 +5574,6 @@
     Page* page = Page::FromAddress(slot_addr);
     DCHECK_EQ(page->owner()->identity(), OLD_SPACE);
     RememberedSet<OLD_TO_NEW>::Remove(page, slot_addr);
-    RememberedSet<OLD_TO_OLD>::Remove(page, slot_addr);
   }
 }
 
@@ -5587,7 +5586,6 @@
     Page* page = Page::FromAddress(start_addr);
     DCHECK_EQ(page->owner()->identity(), OLD_SPACE);
     RememberedSet<OLD_TO_NEW>::RemoveRange(page, start_addr, end_addr);
-    RememberedSet<OLD_TO_OLD>::RemoveRange(page, start_addr, end_addr);
   }
 }