gh-136447: Use self.loop instead of global loop variable in asyncio REPL (GH-136448)

(cherry picked from commit 77fa7a4)

Co-authored-by: Justin Su <[email protected]>

Author: injust

Lib/asyncio/__main__.py

@@ -64,7 +64,7 @@ def callback():
             except BaseException as exc:
                 future.set_exception(exc)
 
-        loop.call_soon_threadsafe(callback, context=self.context)
+        self.loop.call_soon_threadsafe(callback, context=self.context)
 
         try:
             return future.result()