test-loop-block: run in qemu

test-loop-block needs to run in qemu, so we are currently not
testing it in the CI. Run it by itself in a separate job from
TEST-02-UNITTESTS to avoid slowing that suite down.

Fixes https://github.com/systemd/systemd/issues/19966

Disable it in the bionic-* CI for now, as it's affected by
the same uevent ordering issue as TEST-50-DISSECT which makes
it flaky.

test/units/testsuite-61.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=TEST-61-UNITTESTS-QEMU
+
+[Service]
+ExecStartPre=rm -f /failed /testok
+ExecStart=/usr/lib/systemd/tests/testdata/units/%N.sh
+Type=oneshot

test/units/testsuite-61.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+set -eux
+set -o pipefail
+
+TESTS_GLOB="test-loop-block"
+. $(dirname $0)/testsuite-02.sh
+
+exit 0