Fix "invisible" CI tests #3

Job	Run time
build-cache / Build and cache OpenMPI 5	37s
domain-decomp / Run domain decomposition unit tests	1m 5s
pip-install / test-pip-install	1m 4s
adaptivity-serial / Unit and integration tests	1m 4s
integration-dummy / Run dummy	1m 15s
adaptivity-parallel / Unit tests	1m 4s
adaptivity-parallel / Integration tests	1m 17s
coverage / Run test coverage check	1m 16s
unit-tests / unit_tests	1m 4s
	9m 46s

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