Fixing unused Map* in release build

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10442032

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11666 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.cc

@@ -5277,9 +5277,8 @@ class TraversableMap : public Map {
     } else {
       DescriptorArray* descriptor_array =
           static_cast<DescriptorArray*>(object);
-      Object* map =
-          *HeapObject::RawField(descriptor_array, DescriptorArray::kMapOffset);
-      ASSERT(map->IsSmi());
+      ASSERT(*HeapObject::RawField(descriptor_array,
+                                   DescriptorArray::kMapOffset)->IsSmi());
       return descriptor_array;
     }
   }