Fixing unused Map* in release build

src/objects.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5259 matching lines @@
   // Can either be Smi (no instance descriptors), or a descriptor array with the
   // header overwritten as a Smi (thus iterating).
   DescriptorArray* MutatedInstanceDescriptors() {
     Object* object =
         *HeapObject::RawField(this, kInstanceDescriptorsOrBitField3Offset);
     if (object->IsSmi()) {
       return GetHeap()->empty_descriptor_array();
     } 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;
     }
   }
 
   // Start iterating over this map's children, possibly destroying a FixedArray
   // map (see explanation above).
   void ChildIteratorStart() {
     IntrusiveMapTransitionIterator(instance_descriptors()).Start();
     IntrusivePrototypeTransitionIterator(
         unchecked_prototype_transitions()).Start();
@@ skipping 7935 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal