Refactor closure instantiation and inlining

This commit makes several changes related to how closures are handled:

- **Dumper:** Removes redundant introspection of closure ASTs, as this
  is no longer relevant.
- **Optimizer:** Updates `try_inline` to accept `ExecNode` for
  parameters and adds a check to ensure the `function_node` is a
  `Lambda` before attempting inlining.
- **Environment:** Simplifies closure creation by passing an `ExecNode`
  for parameters and ensuring the correct `stack_size` is used.
- **VM:** Adjusts `Closure` to store an `ExecNode` for parameters and
  updates `VM::unpack` to accept an `ExecNode`.

src/ast/environment.rs

@@ -666,14 +666,13 @@ impl Environment {
         } = &node.kind
             && upvalues.is_empty()
         {
-            let stack_size = node.ty.stack_size;
             let closure = Rc::new(crate::ast::vm::Closure::new(
-                params.ty.original.clone(),
+                params.clone(),
                 body.ty.original.clone(),
                 body.clone(),
-                vec![],
+                Vec::new(),
                 *positional_count,
-                stack_size,
+                node.ty.stack_size,
             ));
             let closure_obj: Rc<dyn crate::ast::types::Object> = closure;