Issue #20072: Fixed multiple errors in tkinter with wantobjects is False.

Issue #20072: Fixed multiple errors in tkinter with wantobjects is False.

* Misc.image_names(), Misc.image_types(), Wm.wm_colormapwindows(), and
  LabelFrame.panes() now always return a tuple.
* Fixed _stringify() for non-ASCII strings.
* Fixed error of comparing str and int in tt.LabeledScale._adjust().
* ttk.Notebook.index() now always returns int.
* ttk.Notebook.tabs() now always returns a tuple.
* ttk.Entry.bbox() now always returns a tuple of ints.
* ttk.Entry.validate() now always correctly works.
* ttk.Combobox.current() now always returns int.
* ttk.Panedwindow.sashpos() now always returns int.
* ttk.Treeview.bbox() now always returns a tuple of ints.
* ttk.Treeview.get_children() now always returns a tuple.
* ttk.Treeview.exists() now always correctly works.
* ttk.Treeview.index() now always returns int.
* ttk.Treeview.tag_has() now always returns 0 or 1.
* And numerous other errors in methods which returns a tuple, list or dict.
* Fixed ttk tests for wantobjects is False.