[3.9] bpo-45097: Remove incorrect deprecation warnings in asyncio. (GH-28153)

Deprecation warnings about the loop argument were incorrectly emitted
in cases when the loop argument was used inside the asyncio library,
not from user code.

Lib/asyncio/unix_events.py

@@ -323,7 +323,7 @@ class _UnixSelectorEventLoop(selector_events.BaseSelectorEventLoop):
             server._start_serving()
             # Skip one loop iteration so that all 'loop.add_reader'
             # go through.
-            await tasks.sleep(0, loop=self)
+            await tasks.sleep(0)
 
         return server