According to [0] "Remove the --with-phpunitclass feature since it doesn't work with this scheme." is no longer available which is very unfortunate since we do expect [1] it to be available to make some final clean-up after all tests (success or failure) have been completed before PHPUnit exists.
[0] https://github.com/wikimedia/mediawiki/commit/65adc3734846c685e511e22a2846f53e05e9d80c
[0] https://gerrit.wikimedia.org/r/#/c/mediawiki/core/+/457420/
[1] https://github.com/SemanticMediaWiki/SemanticMediaWiki/pull/3392