bpo-45436: Fix tkinter tests with Tcl/Tk 8.6.11+

[zware]

Since v8.6.11, a few configuration options seem to accept an empty value
where they did not previously; particularly the type of a Menu
widget, and the compound of an ttk widget with a label. Providing an
explicit expected error message to checkEnumParam bypasses the check
of an empty value, which no longer raises TclError.

https://bugs.python.org/issue45436

[zware]

In the interest of greening up a buildbot before another day of sprints starts further east of me, I'm going to go ahead and merge this.

[miss-islington]

Thanks @zware for the PR 🌮🎉.. I'm working now to backport this PR to: 3.9, 3.10.
🐍🍒⛏🤖

[bedevere-bot]

GH-29080 is a backport of this pull request to the 3.10 branch.

[bedevere-bot]

GH-29081 is a backport of this pull request to the 3.9 branch.

[miss-islington]

Thanks @zware for the PR 🌮🎉.. I'm working now to backport this PR to: 3.8.
🐍🍒⛏🤖

[bedevere-bot]

GH-29093 is a backport of this pull request to the 3.8 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot x86-64 macOS 3.9 has failed when building commit 15cd7a7.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/108/builds/308) and take a look at the build logs.
4. Check if the failure is related to this commit (15cd7a7) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/108/builds/308

Failed tests:

• test_importlib

Failed subtests:

• test_multiprocessing_pool_circular_import - test.test_importlib.test_threaded_import.ThreadedImportTests

Summary of the results of the build (if available):

== Tests result: FAILURE then FAILURE ==

406 tests OK.

10 slowest tests:

• test_concurrent_futures: 4 min 47 sec
• test_multiprocessing_spawn: 4 min 1 sec
• test_unparse: 3 min 37 sec
• test_tokenize: 3 min 18 sec
• test_multiprocessing_forkserver: 2 min 24 sec
• test_lib2to3: 2 min 13 sec
• test_unicodedata: 1 min 48 sec
• test_asyncio: 1 min 40 sec
• test_capi: 1 min 35 sec
• test_io: 1 min 4 sec

1 test failed:
test_importlib

18 tests skipped:
test_devpoll test_epoll test_gdb test_ioctl test_msilib
test_multiprocessing_fork test_ossaudiodev test_smtpnet test_spwd
test_ssl test_startfile test_tix test_tk test_ttk_guionly
test_winconsoleio test_winreg test_winsound test_zipfile64

1 re-run test:
test_importlib

Total duration: 27 min 35 sec

Click to see traceback logs

Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/test/test_importlib/test_threaded_import.py", line 258, in test_multiprocessing_pool_circular_import
    script_helper.assert_python_ok(fn)
  File "/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/test/support/script_helper.py", line 156, in assert_python_ok
    return _assert_python(True, *args, **env_vars)
  File "/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/test/support/script_helper.py", line 142, in _assert_python
    res.fail(cmd_line)
  File "/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/test/support/script_helper.py", line 70, in fail
    raise AssertionError("Process return code is %d\n"
AssertionError: Process return code is 1
command line: ['/Users/buildbot/buildarea/3.9.billenstein-macos/build/python.exe', '-X', 'faulthandler', '-I', '/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/test/test_importlib/partial/pool_in_threads.py']


Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/multiprocessing/resource_tracker.py", line 201, in main
    cache[rtype].remove(name)
KeyError: '/psm_d8252cd5'


Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.9.billenstein-macos/build/Lib/multiprocessing/resource_tracker.py", line 201, in main
    cache[rtype].remove(name)
KeyError: '/psm_7faeecfe'