gh-124111: test macOS CI with Tk 9

[hugovk]

Includes #136959 and fixes the tests for Tcl/Tk 9.

New PR because I couldn't push to that one:

Details

❯ git push
Enumerating objects: 13, done.
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Total 7 (delta 6), reused 0 (delta 0), pack-reused 0 (from 0)
remote: Resolving deltas: 100% (6/6), completed with 6 local objects.
remote: error: GH006: Protected branch update failed for refs/heads/gh-124111-macos-ci-tk9.
remote:
remote: - Changes must be made through a pull request.
To https://github.com/ned-deily/cpython.git
 ! [remote rejected]         gh-124111-macos-ci-tk9 -> gh-124111-macos-ci-tk9 (protected branch hook declined)
error: failed to push some refs to 'https://github.com/ned-deily/cpython.git'

[ned-deily]

FYI @culler @serhiy-storchaka

[culler]

Thanks for the good news!

By the way, Tcl/Tk 9.0.2 was released on July 2.

[hugovk]

Should we backport?

In #124111 (comment), @serhiy-storchaka said:

• Any test changes should be backported. This would help future bugfix backports and help to compare versions if we have a regression. Tests should be passed with older Tcl/Tk versions.

So backport the test changes to 3.13, but leave macOS CI on tcl-tk@8?

[ned-deily]

Probably. And backport the whole PR to 3.14. But it might be good to wait for 3.15.0a1 to get out the door first.