Revert of Merge cellspace into old pointer space

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 380e19a95ca06e8aa6ad5c683090407a19a5d65f..7ba625442369de1f1f0dd57ac262c03196c90bae 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -665,6 +665,7 @@
   MAP_TYPE,
   CODE_TYPE,
   ODDBALL_TYPE,
+  CELL_TYPE,
 
   // "Data", objects that cannot contain non-map-word pointers to heap
   // objects.
@@ -719,7 +720,6 @@
   FIXED_ARRAY_TYPE,
   CONSTANT_POOL_ARRAY_TYPE,
   SHARED_FUNCTION_INFO_TYPE,
-  CELL_TYPE,
   WEAK_CELL_TYPE,
   PROPERTY_CELL_TYPE,
   PROTOTYPE_INFO_TYPE,
@@ -9777,6 +9777,7 @@
 
   static inline Cell* FromValueAddress(Address value) {
     Object* result = FromAddress(value - kValueOffset);
+    DCHECK(result->IsCell());
     return static_cast<Cell*>(result);
   }