avm1: Root clip should not have a name

Previously we set the name of the root clip to `_level0`. Top-level
clips should actually have no name (`_root._name` returns `""`).

However, when constructing a dot path, `_level0` still gets inserted
by `DisplayObject::path` for the top-level, so that `trace(_root)`
still correctly prints `_level0`.

TODO: When `loadMovieNum` gets merged in, the proper level # needs
to be returned by `.DisplayObject::path`.

core/src/display_object.rs

@@ -575,7 +575,8 @@ pub trait TDisplayObject<'gc>: 'gc + Collect + Debug {
             path.push_str(&*self.name());
             path
         } else {
-            self.name().to_string()
+            // TODO: Get the actual level # from somewhere.
+            "_level0".to_string()
         }
     }
 

core/src/player.rs

@@ -237,7 +237,6 @@ impl<
             let root_data = gc_root.0.write(gc_context);
             let mut root = root_data.root;
             root.post_instantiation(gc_context, root, root_data.avm.prototypes().movie_clip);
-            root.set_name(gc_context, "_level0");
         });
 
         player.build_matrices();