Change automatically generated tkinter.Checkbutton widget names to
avoid collisions with automatically generated tkinter.ttk.Checkbutton
widget names within the same parent widget.
Previously, checkbuttons in different parent widgets could have the same
short name and share the same state if arguments "name" and "variable" are
not specified. Now they are globally unique.
* Move Lib/tkinter/test/test_tkinter/ to Lib/test/test_tkinter/.
* Move Lib/tkinter/test/test_ttk/ to Lib/test/test_ttk/.
* Add Lib/test/test_ttk/__init__.py based on test_ttk_guionly.py.
* Add Lib/test/test_tkinter/__init__.py
* Remove old Lib/test/test_tk.py.
* Remove old Lib/test/test_ttk_guionly.py.
* Add __main__ sub-modules.
* Update imports and update references to rename files.
Serhiy Storchaka
Alex Waygood
Victor Stinner