When the previous build exists, use its packing structure otherwise container-encapsulate
generates a new one

See: coreos#3243
See: https://cloud.google.com/blog/products/identity-security/rsa-snp-vm-more-confidential
Fixes: https://issues.redhat.com/browse/COS-2343

coreos#3344

We bubble denylisted tests with 'Warn: true' option as warnings rather than hard failures:
```
kola -p qemu run --parallel 8 ext.config.ntp.* --output-dir tmp/kola

⏭️  Skipping kola test pattern "ext.config.ntp.chrony.dhcp-propagation":
  👉 coreos/fedora-coreos-tracker#1508
⚠️  Warning kola test pattern "ext.config.ntp.timesyncd.dhcp-propagation", snoozing expired on Jul 20 2023:
  👉 coreos/fedora-coreos-tracker#1508
=== RUN   ext.config.ntp.chrony.coreos-platform-chrony-config
=== RUN   ext.config.ntp.timesyncd.dhcp-propagation
--- PASS: ext.config.ntp.chrony.coreos-platform-chrony-config (27.56s)
--- WARN: ext.config.ntp.timesyncd.dhcp-propagation (90.72s)
        cluster.go:162: Error: Unit kola-runext.service exited with code 1
        cluster.go:162: 2023-07-27T06:24:18Z cli: Unit kola-runext.service exited with code 1
        harness.go:1236: kolet failed: : kolet run-test-unit failed: Process exited with status 1
FAIL, output in tmp/kola
+ rc=0
+ set +x
```

Co-authored-by: Dusty Mabe <[email protected]>

With the introduction of warn: true the logic gets complicated.
This is an attempt to simplify the logic and handle all corner cases.

Signed-off-by: Renata Ravanelli <[email protected]>

 - Add check_tag, to check if the tag was added to the build;
 - Add ensure_tag, if the tag is not part of the build, add it.

Signed-off-by: Renata Ravanelli <[email protected]>

The offline detection in our testiso tests is not working properly
meaning we are never running offline tests today. Let's fix that
here by parsing it properly.

Fixes f98481f.

After rawhide was updated to systemd 254+ we started seeing failures in
ppc64le/s390x where checking the ignition-ostree-growfs.service (part
of the `basic/FCOSGrowpart` test would fail because multiple entries
(lines) would be returned in the
`journalctl -o json MESSAGE_ID=39f53479d3a045ac8e11786248231fbf UNIT=ignition-ostree-growfs.service`
call:

```
 --- FAIL: basic (41.40s)
         cluster.go:94: kolet:
 2023-08-16T03:42:44Z kolet: Error getting journalclt output for ignition-ostree-growfs.service: invalid character '{' after top-level value. Out: {"JOB_ID":"68","SYSLOG_IDENTIFIER":"systemd","PRIORITY":"6","__SEQNUM":"384","__SEQNUM_ID":"18eec6fe008c40a9a6cffc2e9397e0b6","CODE_LINE":"796","_TRANSPORT":"journal","TID":"1","__REALTIME_TIMESTAMP":"1692157339095636","_SELINUX_CONTEXT":"kernel","SYSLOG_FACILITY":"3","_SYSTEMD_CGROUP":"/init.scope","_GID":"0","__CURSOR":"s=18eec6fe008c40a9a6cffc2e9397e0b6;i=180;b=4e0b76a0cfa44247ba229413f78e95f0;m=be48b8;t=603021519d254;x=363c4c17ec8cd6cc","_MACHINE_ID":"e5611e01502c4799bde984942694b30c","MESSAGE_ID":"39f53479d3a045ac8e11786248231fbf","_PID":"1","CODE_FILE":"src/core/job.c","_SYSTEMD_UNIT":"init.scope","_SOURCE_REALTIME_TIMESTAMP":"1692157339095627","_EXE":"/usr/lib/systemd/systemd","_CAP_EFFECTIVE":"1ffffffffff","JOB_TYPE":"start","_BOOT_ID":"4e0b76a0cfa44247ba229413f78e95f0","UNIT":"ignition-ostree-growfs.service","_COMM":"systemd","_HOSTNAME":"localhost","INVOCATION_ID":"b49823ed3a4948048ae303deb5351dd1","JOB_RESULT":"done","_SYSTEMD_SLICE":"-.slice","CODE_FUNC":"job_emit_done_message","_CMDLINE":"/init","__MONOTONIC_TIMESTAMP":"12470456","_RUNTIME_SCOPE":"initrd","_UID":"0","MESSAGE":"Finished ignition-ostree-growfs.service - Ignition OSTree: Grow Root Filesystem."}
 {"_SYSTEMD_CGROUP":"/init.scope","SYSLOG_FACILITY":"3","_SYSTEMD_UNIT":"init.scope","CODE_LINE":"796","_EXE":"/usr/lib/systemd/systemd","MESSAGE":"Finished ignition-ostree-growfs.service - Ignition OSTree: Grow Root Filesystem.","UNIT":"ignition-ostree-growfs.service","JOB_ID":"68","_SOURCE_REALTIME_TIMESTAMP":"1692157339095627","_SYSTEMD_SLICE":"-.slice","_GID":"0","_CAP_EFFECTIVE":"1ffffffffff","SYSLOG_IDENTIFIER":"systemd","CODE_FILE":"src/core/job.c","CODE_FUNC":"job_emit_done_message","_COMM":"systemd","_RUNTIME_SCOPE":"initrd","PRIORITY":"6","JOB_RESULT":"done","__SEQNUM":"1341","_TRANSPORT":"journal","JOB_TYPE":"start","INVOCATION_ID":"b49823ed3a4948048ae303deb5351dd1","_UID":"0","__CURSOR":"s=18eec6fe008c40a9a6cffc2e9397e0b6;i=53d;b=4e0b76a0cfa44247ba229413f78e95f0;m=be48b8;t=603021519d254;x=363c4c17ec8cd6cc","_BOOT_ID":"4e0b76a0cfa44247ba229413f78e95f0","_CMDLINE":"/init","__SEQNUM_ID":"18eec6fe008c40a9a6cffc2e9397e0b6","_HOSTNAME":"localhost","_PID":"1","__REALTIME_TIMESTAMP":"1692157339095636","__MONOTONIC_TIMESTAMP":"12470456","TID":"1","_SELINUX_CONTEXT":"kernel","MESSAGE_ID":"39f53479d3a045ac8e11786248231fbf","_MACHINE_ID":"e5611e01502c4799bde984942694b30c"}
     --- FAIL: basic/FCOSGrowpart (0.18s)
```

Apparently it was picking up an entry from /run/log/journal and another
one from /var/log/journal. The entries are almost completely identical,
including __SEQNUM_ID, _SOURCE_REALTIME_TIMESTAMP, etc. Here is one example
diff:

```
[core@cosa-devsh ~]$ diff -ur foo1.json foo2.json
--- foo1.json   2023-08-16 13:51:18.406733458 +0000
+++ foo2.json   2023-08-16 13:51:10.336733458 +0000
@@ -30,9 +30,9 @@
   "_SYSTEMD_UNIT": "init.scope",
   "_TRANSPORT": "journal",
   "_UID": "0",
-  "__CURSOR": "s=a28672494c644ba48c9b909e39681e91;i=17d;b=750a68e68fa045dd884bb1b5a1e40b50;m=72eaf9;t=6030a8488adf8;x=e7da920318b458f1",
+  "__CURSOR": "s=a28672494c644ba48c9b909e39681e91;i=551;b=750a68e68fa045dd884bb1b5a1e40b50;m=72eaf9;t=6030a8488adf8;x=e7da920318b458f1",
   "__MONOTONIC_TIMESTAMP": "7531257",
   "__REALTIME_TIMESTAMP": "1692193568370168",
-  "__SEQNUM": "381",
+  "__SEQNUM": "1361",
   "__SEQNUM_ID": "a28672494c644ba48c9b909e39681e91",
 }
```

It shows only the __SEQNUM and __CURSOR are different.

Suffice it to say that these messages are from the same service run and that
the service didn't run twice.

Let's workaround this by only considering the on disk journal, which would
have been flushed too in early boot, so should have all the logs we need.