gh-87179: Fix more IDLE class headers (#96899)

Remove unneeded '(object)' and '()'.

Lib/idlelib/idle_test/test_text.py

@@ -6,7 +6,7 @@
 from test.support import requires
 from _tkinter import TclError
 
-class TextTest(object):
+class TextTest:
     "Define items common to both sets of tests."
 
     hw = 'hello\nworld'  # Several tests insert this after initialization.

Lib/idlelib/idle_test/test_zzdummy.py

@@ -19,7 +19,7 @@
 }
 code_sample = """\
 
-class C1():
+class C1:
     # Class comment.
     def __init__(self, a, b):
         self.a = a