[PR #9678/7d2afcf4 backport][3.11] Remove dead code from WebSocketResponse.receive (#9682)

Co-authored-by: J. Nick Koston <[email protected]>

Author: patchback[bot]

aiohttp/web_ws.py

@@ -509,8 +509,6 @@ async def receive(self, timeout: Optional[float] = None) -> WSMessage:
         if self._reader is None:
             raise RuntimeError("Call .prepare() first")
 
-        loop = self._loop
-        assert loop is not None
         receive_timeout = timeout or self._receive_timeout
         while True:
             if self._waiting: