* 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.
- Emscripten's default umask is too strict, see
https://github.com/emscripten-core/emscripten/issues/17269
- getuid/getgid and geteuid/getegid are stubs that always return 0
(root). Disable effective uid/gid syscalls and fix tests that use
chmod() current user.
- Cannot drop X bit from directory.
- Mark more ``umask()`` cases
- ``dup()`` is not supported
- ``/dev/null`` is not available
- document missing features
- mark more modules as not available
* ``sys.executable`` is not set
* WASI does not support subprocess
* ``pwd`` module is not available
* WASI checks ``open`` syscall flags more strict, needs r, w, rw flag.
* ``umask`` is not available
* ``/dev/null`` may not be accessible
- WASI's ``gethostname()`` is a stub that always fails with OSError
``ENOTSUP``
- skip mailcap ``test`` if subprocess is not available
- WASI process_time clock does not work.
- fd inheritance can't be modified because Emscripten doesn't support subprocesses anyway.
- setpriority always fails
- geteuid no longer causes problems with latest emsdk
- umask is a stub
- geteuid / getuid always return 0, but process cannot chown to random uid.
- getgroups always fails.
- geteuid and getegid always return 0 (root), which confuse tarfile and
tests.
- hardlinks (link, linkat) always fails.
- non-encodable file names are not supported by NODERAWFS layer.
- mark more tests with dependency on subprocess and multiprocessing.
Mocking does not work if the module fails to import.