tests

Fix unnecessary mut #222

Job	Run time
tests (Mac OS 12.latest)	10m 3s
tests (Centos 8, ubuntu-latest, centos8)	4m 22s
tests (Mac OS 13.latest)	4m 50s
tests (Fedora 32, ubuntu-latest, fedora32)	4m 26s
tests (Fedora 33, ubuntu-latest, fedora33)	4m 9s
tests (Fedora 34, ubuntu-latest, fedora34)	4m 25s
tests (Fedora 35, ubuntu-latest, fedora35)	4m 55s
tests (Debian Testing, ubuntu-latest, debiantesting)	3m 34s
tests (Ubuntu 18.04, ubuntu-latest, ubuntu1804)	3m 54s
tests (Ubuntu 20.04, ubuntu-latest, ubuntu2004)	4m 19s
tests (Ubuntu 22.04, ubuntu-latest, ubuntu2204)	3m 49s
tests (OpenSUSE 15, ubuntu-latest, opensuse15)	4m 21s
tests (Archlinux Base (Rolling), ubuntu-latest, arch)	3m 55s
	1h 1m 2s

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