mantle/kola/harness: disallow AppendKernelArgs for non-Exclusive tests

[dustymabe]

If a test is modifying kernel arguments it's almost by defnition not
friendly to other tests. Let's detect this and error out.

This would have saved me some time as I was hacking around locally.

[dustymabe]

hmm CI failed with:

ERROR: Unable to pull Docker image "image-registry.openshift-image-registry.svc:5000/coreos-ci/coreos-ci-coreos-assembler-bb142490-2eba-492a-a687-93cbfb4589e9@sha256:81101dd89c703e9b685672c2fa750586d726688ffc89cb83381f1e242f440f54". Check if image tag name is spelled correctly.```

Will run again.

[saqibali-2k]

Basic tests failed, saw this in ignition files stage:

[    8.379743] ignition[862]: CRITICAL : files: ensureUsers: op(1): [failed]   creating or modifying user "core": exit status 10: Cmd: "useradd" "--root" "/sysroot" "--create-home" "--password" "*" "--comment" "CoreOS Admin" "--groups" "adm,sudo,systemd-journal,wheel" "core" Stdout: "" Stderr: "useradd: lock /etc/group.lock already used by PID 4\nuseradd: cannot lock /etc/group; try again later.\n"
[    8.385431] ignition[862]: files failed
[    8.385431] ignition[862]: files failed
[    8.386157] ignition[862]: Full config:
[    8.386950] ignition[862]: {
[�[0;32m  OK  �[0m] Closed �[0;1;39mdbus.socket�[0m - D-Bus System Message Bus Socket.
[    8.388948] ignition[862]:   "ignition": {
[    8.389736] ignition[862]:     "config": {
[    8.390503] ignition[862]:       "replace": {
[�[0;32m  OK  �[0m] Stopped �[0;1;39mcoreos-touch-run-a… CoreOS: Touch /run/agetty.reload.
[    8.392850] ignition[862]:         "verification": {}
[    8.393805] ignition[862]:       }
[    8.394411] ignition[862]:     },
[    8.395087] ignition[862]:     "proxy": {},
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-fetch-off…ce�[0m - Ignition (fetch-offline).
[    8.397165] ignition[862]:     "security": {
[    8.397974] ignition[862]:       "tls": {}
[�[0;32m  OK  �[0m] Stopped �[0;1;39mcoreos-ignition-se…CoreOS Ignition User Config Setup.
[    8.400122] ignition[862]:     },
[    8.400748] ignition[862]:     "timeouts": {},
[    8.401645] ignition[862]:     "version": "3.4.0-experimental"
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-ostree-ch…STree: Check Root Filesystem Size.
[    8.404148] ignition[862]:   },
[    8.404813] ignition[862]:   "kernelArguments": {},
[    8.405775] ignition[862]:   "passwd": {
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-ostree-po…ervice�[0m - Populate OSTree /var.
         Stopping �[0;1;39mignition-mount.service�[0m - Ignition (mount)...
[    8.413297] ignition[862]:     "users": [
[    8.414075] ignition[862]:       {
[    8.416298] ignition[862]:         "gecos": "CoreOS Admin",
[    8.417352] ignition[862]:         "groups": [
[    8.418159] ignition[862]:           "adm",
[    8.418933] ignition[862]:           "sudo",
[    8.424199] ignition[862]:           "systemd-journal",
[    8.425150] ignition[862]:           "wheel"
[    8.425910] ignition[862]:         ],
[    8.426529] ignition[862]:         "name": "core",
[    8.430282] ignition[862]:         "sshAuthorizedKeys": [
[    8.431201] ignition[862]:           "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQD3lxQbxFpPmH9JGQcSaK/TFOLqP9L0vE7u0wahHsMJ+FJsdETZLY7N0kmiKOFFl5uB3wZlTq69xH2w43K78SlT8R6KM3Y+DYrGJRU6wwwGaPjp8ip2lqT7jKo7Pe0viokw9KitzTF0GQucJrn7gHgo63CrPnwoy+DLyFZAX5SmjL3UHDAFGgnqE+a2HJ6URmpa+hGOOC89xXUeoodc+EhuGmYr2Nesvts1slDfmSgOwbG4Sy/meEPzs31PUJSOYcLiEIDoPKEpESM5zWE8tBmZ6+lgZgmXNLkKnfdNWwHYZRliVCMvA9HD6utRFwk/pyMw5FitXmzqYhjw9NHugui5 core@default"
[    8.440871] ignition[862]:         ]
[    8.441542] ignition[862]:       }
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-mount.service�[0m - Ignition (mount).
         Stopping �[0;1;39mignition-ostree-m…service�[0m - Mount OSTree /var...
[    8.450192] ignition[862]:     ]
[    8.450884] ignition[862]:   },
[    8.452040] ignition[862]:   "storage": {
[    8.452846] ignition[862]:     "files": [
[    8.453578] ignition[862]:       {
[    8.454194] ignition[862]:         "group": {},
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-ostree-mo…r.service�[0m - Mount OSTree /var.
[�[0;32m  OK  �[0m] Stopped target �[0;1;39minitrd-root…get�[0m - Initrd Root File System.
[    8.457653] ignition[862]:         "path": "/etc/zincati/config.d/90-disable-auto-updates.toml",
[    8.459104] ignition[862]:         "user": {},
[�[0;32m  OK  �[0m] Stopped �[0;1;39mdracut-pre-mount.service�[0m - dracut pre-mount hook.
[    8.461146] ignition[862]:         "contents": {
[    8.462083] ignition[862]:           "source": "data:text/plain;charset=utf-8;base64,W3VwZGF0ZXNdCmVuYWJsZWQgPSBmYWxzZQ==",
[�[0;32m  OK  �[0m] Stopped �[0;1;39mdracut-initqueue.service�[0m - dracut initqueue hook.
[    8.465346] ignition[862]:           "verification": {}
[    8.466363] ignition[862]:         },
[    8.467041] ignition[862]:         "mode": 420
[    8.467765] ignition[862]:       }
[�[0;32m  OK  �[0m] Stopped �[0;1;39mostree-prepare-root.service�[0m - OSTree Prepare OS/.
[    8.469514] ignition[862]:     ]
[    8.470142] ignition[862]:   },
[    8.470769] ignition[862]:   "systemd": {
[    8.471535] ignition[862]:     "units": [
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-ostree-gr…tion OSTree: Grow root filesystem.
[    8.473510] ignition[862]:       {
[    8.474115] ignition[862]:         "enabled": true,
[    8.475005] ignition[862]:         "name": "afterburn-sshkeys@core.service"
[    8.476389] ignition[862]:       }
[    8.477088] ignition[862]:     ]
[�[0;32m  OK  �[0m] Stopped �[0;1;39mignition-ostree-mo…STree: Mount (firstboot) /sysroot.
[    8.479250] ignition[862]:   }
[    8.479907] ignition[862]: }
[    8.481061] systemd[1]: ignition-files.service: Failed with result 'exit-code'.