bpo-43013: Update idlelib code to 3.x  (GH-24315)

Remove 9 remaining '(object)' occurrences in class headers in idlelib
and 25 '()' occurrences in idlelib.idle_test class headers.
diff --git a/Lib/idlelib/run.py b/Lib/idlelib/run.py
index 1e84ecc..ec575c3 100644
--- a/Lib/idlelib/run.py
+++ b/Lib/idlelib/run.py
@@ -538,7 +538,7 @@ def decode_interrupthook(self):
         thread.interrupt_main()
 
 
-class Executive(object):
+class Executive:
 
     def __init__(self, rpchandler):
         self.rpchandler = rpchandler