test: Drop duplicate cleanup of admin processes

The nondestructive `_terminate_sessions` runs before our cleanups and
already calls `pkill -9 -u admin`.

Author: jelly

test/machineslib.py

@@ -494,13 +494,6 @@ def stop_all() -> None:
         else:
             m.execute("systemctl reset-failed libvirtd; systemctl try-restart libvirtd")
 
-        # user libvirtd instance tends to SIGABRT with "Failed to find user record for uid .." on shutdown
-        # during cleanup so make sure that there are no leftover user processes that bleed into the next test
-        self.addCleanup(m.execute, """
-            pkill -u admin || true;
-            while [ -n "$(pgrep -au admin | grep -v 'systemd --user')" ]; do sleep 0.5; done
-        """)
-
         # FIXME: report downstream; AppArmor noisily denies some operations, but they are not required for us
         self.allow_journal_messages(r'.* type=1400 .* apparmor="DENIED" operation="capable" profile="\S*libvirtd.* capname="sys_rawio".*')  # noqa: E501
         # AppArmor doesn't like the non-standard path for our storage pools