* Introduce FunctionReferenceRegistrar
- Track function references created by functors
- Remove ValueStack-held attributes for functors
- Add Function References section to escript program
- Use Function References section in ins_functor
- Update escript version
* Update listfile snapshots
- Remove ValueStack-held attributes created by functors
* Add function reference tracking to function references
- `emit.function_reference` uses funcref registrar + emits that index
- `ins_funcref` uses parameter count + is variadic from prog funcref table
- update listfile snapshots
* Add core-changes
