fix test_browsingContext_close_last

tests/browsing_context/test_close.py

@@ -50,10 +50,7 @@ async def test_browsingContext_close_last(websocket, context_id):
 
     try:
         result = await get_tree(websocket)
-        assert result == AnyExtending(
-            {'contexts': [{
-                "context": context_id,
-            }]})
+        assert result['contexts'] == []
     except websockets.exceptions.ConnectionClosedError:
         # Chromedriver closes the connection after the last context (not
         # counting the mapper tab) is closed. NodeJS runner does not.