* Unit tests: replace mock and compat with code from community.internal_test_tools (#9921)
* Replace compat with equivalent from community.internal_test_tools.
* Replace mock with equivalent from community.internal_test_tools.
* Remove ignore.txt entries.
* Add test that's no longer present in later versions.
* Fix more typos in plugins/.
* Fix typos in tests/unit/.
* Fix typos in tests/integration/.
* Fix more typos.
Co-authored-by: Sebastian Gumprich <rndmh3ro@users.noreply.github.com>
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Co-authored-by: Sebastian Gumprich <rndmh3ro@users.noreply.github.com>