refactor: remove redundant clone in UnboxLibfuncWrapped::specialize_signature

[Fibonacci747]

Summary

• Fetch zero_sized property before box_ty() call
• Remove second .clone() by moving ty directly into OutputVarInfo
• Reduces unnecessary allocations in boxing signature specialization

---

Type of change

• Performance improvement

---

Why is this change needed?

The original code had two .clone() calls on ty:

1. One for box_ty()

   cairo/crates/cairo-lang-sierra/src/extensions/modules/boxing.rs

   Lines 52 to 58 in 34c3412

   	/// Helper for getting the `Box<T>` type.
   	pub fn box_ty(
   	context: &dyn SignatureSpecializationContext,
   	ty: ConcreteTypeId,
   	) -> Result<ConcreteTypeId, SpecializationError> {
   	context.get_wrapped_concrete_type(BoxType::id(), ty)
   	}

   consumption
2. One for OutputVarInfo.ty before borrow in get_type_info()

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[reviewable-StarkWare]

This change is 

[orizi]

@orizi made 1 comment.
Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @Fibonacci747).

---

crates/cairo-lang-sierra/src/extensions/modules/boxing.rs line 127 at r1 (raw file):

                    OutputVarReferenceInfo::Deferred(DeferredOutputKind::Generic)
                },
            }],

Suggestion:

        let ref_info = if context.get_type_info(&ty)?.zero_sized {
            OutputVarReferenceInfo::ZeroSized
        } else {
            OutputVarReferenceInfo::Deferred(DeferredOutputKind::Generic)
        };
        Ok(LibfuncSignature::new_non_branch(
            vec![box_ty(context, ty.clone())?],
            vec![OutputVarInfo { ty, ref_info }],