Remove un-needed __hash__ methods from stdlib (#8465)

stdlib/asyncio/events.pyi

@@ -85,7 +85,6 @@ class TimerHandle(Handle):
         loop: AbstractEventLoop,
         context: Context | None = ...,
     ) -> None: ...
-    def __hash__(self) -> int: ...
     def when(self) -> float: ...
     def __lt__(self, other: TimerHandle) -> bool: ...
     def __le__(self, other: TimerHandle) -> bool: ...