bpo-45160: Fix refleak in test_ttk_guionly introduced in GH-28291

[ambv]

The closure in cb_test was the root cause of the refleak, to address it we're taking the callback handle and deleting it when we don't need it anymore. Additionally, other tests explicitly destroy OptionMenu objects to avoid issues with reference cycles.

Before the change

0:00:00 load avg: 4.23 Run tests sequentially
0:00:00 load avg: 4.23 [1/1] test_ttk_guionly
beginning 9 repetitions
123456789
.........
test_ttk_guionly leaked [63, 63, 63, 63] references, sum=252
test_ttk_guionly leaked [31, 31, 31, 31] memory blocks, sum=124
test_ttk_guionly failed (reference leak)

== Tests result: FAILURE ==

After the change

0:00:00 load avg: 10.33 Run tests sequentially
0:00:00 load avg: 10.33 [1/1] test_ttk_guionly
beginning 9 repetitions
123456789
.........

== Tests result: SUCCESS ==

https://bugs.python.org/issue45160

[ambv]

Fix confirmed on the Windows 8.1 refleak buildbot:

0:36:09 load avg: 5.80 [146/425] test_imghdr passed -- running: test_io (5 min 9 sec), test_pickle (4 min 17 sec), test_nntplib (1 min)
beginning 6 repetitions
123456
......
0:36:28 load avg: 5.15 [147/425] test_ttk_guionly passed -- running: test_io (5 min 28 sec), test_pickle (4 min 36 sec), test_nntplib (1 min 19 sec)
beginning 6 repetitions
123456
......

Build link: https://buildbot.python.org/all/#/builders/443/builds/9

[miss-islington]

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

[miss-islington]

Sorry @ambv, I had trouble checking out the 3.10 backport branch.
Please backport using cherry_picker on command line.
cherry_picker 54d1e3f72ed1ad8e860888c30ee7a285b931c0d1 3.10

[bedevere-bot]

GH-29420 is a backport of this pull request to the 3.9 branch.

[miss-islington]

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

[miss-islington]

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