When `systemd` is run in the TEST_RUN_MINIMAL mode, it doesn't really
set up cgroups, so it shouldn't try to remove anything.
Closes https://github.com/systemd/systemd/issues/8474.
/* We can't really delete the group, since we are in it. But
* let's trim it. */
- if (delete && m->cgroup_root)
+ if (delete && m->cgroup_root && m->test_run_flags != MANAGER_TEST_RUN_MINIMAL)
(void) cg_trim(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, false);
m->cgroup_empty_event_source = sd_event_source_unref(m->cgroup_empty_event_source);