WIP: Fix Free at exit

I don't think this is the correct fix. There's an object that has enough
flags to identify as a T_DATA, but everything else is NULL.

When free at exit is running, we end up trying to free it's object_id,
which at the moment is naively assuming that we can just look up the
shape and it'll be fine, but the shape lookup is returning NULL in this
case and so the flag check on the shape is failing.

what I've done here is almost certainly not the correct fix, but I just
want FREE_AT_EXIT to be quiet, so I can see the proper issues in the CI
tests.

Author: eightbitraptor

shape.h

@@ -238,7 +238,8 @@ bool rb_shape_set_shape_id(VALUE obj, shape_id_t shape_id);
 static inline bool
 rb_shape_obj_has_id(VALUE obj)
 {
-    return rb_shape_has_object_id(rb_shape_get_shape(obj));
+    shape_id_t shape_id = rb_shape_get_shape_id(obj);
+    return (shape_id != ROOT_SHAPE_ID) && rb_shape_has_object_id(rb_shape_get_shape_by_id(shape_id));
 }
 
 VALUE rb_obj_debug_shape(VALUE self, VALUE obj);