[3.12] gh-116484: Fix collisions between Checkbutton and ttk.Checkbutton default names (GH-116495) (GH-116901)

Change automatically generated tkinter.Checkbutton widget names to
avoid collisions with automatically generated tkinter.ttk.Checkbutton
widget names within the same parent widget.
(cherry picked from commit c61cb507c10c5b597928284e087a9a384ab267d0)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>