Revert of Merge cellspace into old pointer space

src/heap/mark-compact.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_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 262 matching lines @@
     if (slot >= reinterpret_cast<ObjectSlot>(NUMBER_OF_SLOT_TYPES)) {
       DCHECK_NOT_NULL(*slot);
     }
 #endif
     slots_[idx_++] = slot;
   }
 
   enum SlotType {
     EMBEDDED_OBJECT_SLOT,
     RELOCATED_CODE_OBJECT,
-    CELL_TARGET_SLOT,
     CODE_TARGET_SLOT,
     CODE_ENTRY_SLOT,
     DEBUG_TARGET_SLOT,
     JS_RETURN_SLOT,
     NUMBER_OF_SLOT_TYPES
   };
 
   static const char* SlotTypeToString(SlotType type) {
     switch (type) {
       case EMBEDDED_OBJECT_SLOT:
         return "EMBEDDED_OBJECT_SLOT";
       case RELOCATED_CODE_OBJECT:
         return "RELOCATED_CODE_OBJECT";
-      case CELL_TARGET_SLOT:
-        return "CELL_TARGET_SLOT";
       case CODE_TARGET_SLOT:
         return "CODE_TARGET_SLOT";
       case CODE_ENTRY_SLOT:
         return "CODE_ENTRY_SLOT";
       case DEBUG_TARGET_SLOT:
         return "DEBUG_TARGET_SLOT";
       case JS_RETURN_SLOT:
         return "JS_RETURN_SLOT";
       case NUMBER_OF_SLOT_TYPES:
         return "NUMBER_OF_SLOT_TYPES";
@@ skipping 651 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_MARK_COMPACT_H_