Fixing unused Map* in release build

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index fd55f24979bcf78dc944e33f09635ca93e1855d8..794234be5035b74efd3fcef9980d7eec8db4c064 100644
--- a/src/objects.cc
+++ b/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;
     }
   }