avm1: Allow string paths in hitTest (fix #1559)

core/src/avm1/globals/movie_clip.rs

@@ -138,11 +138,8 @@ pub fn hit_test<'gc>(
             return Ok(ret.into());
         }
     } else if args.len() == 1 {
-        let other = args
+        let other = activation
-            .get(0)
+            .resolve_target_display_object(movie_clip.into(), args.get(0).unwrap().clone())?;
-            .unwrap()
-            .coerce_to_object(activation)
-            .as_display_object();
         if let Some(other) = other {
             return Ok(other
                 .world_bounds()

core/tests/swfs/avm1/movieclip_hittest/output.txt

@@ -66,3 +66,15 @@ true
 // circle.hitTest(upper)
 true
 
+// String path, below and to the right of the circle, overlapping only with BB.
+// circle.hitTest('_root.lower')
+true
+
+// String path, above and to the right of the circle.
+// circle.hitTest('../upper')
+true
+
+// String path, /
+// circle.hitTest('/')
+true
+