[K/N] Simplify ObjectFactory ^KT-51436

Merge-request: KT-MR-5958
Merged-by: Alexander Shabalin <Alexander.Shabalin@jetbrains.com>

kotlin-native/runtime/src/main/cpp/Memory.h

@@ -93,6 +93,7 @@ struct ObjHeader {
   }
 
   // Unsafe cast to ArrayHeader. Use carefully!
+  // TODO: RuntimeAssert on type_info()->IsArray()?
   ArrayHeader* array() { return reinterpret_cast<ArrayHeader*>(this); }
   const ArrayHeader* array() const { return reinterpret_cast<const ArrayHeader*>(this); }