tests: stop using ubi8 (this is the "0x3c" flake)

[edsantiago]

Use of ubi8 images is causing one of our big flakes, mostly in podman (because it runs many more CI jobs than buildah) but also in buildah CI:

$ buildah build -f Containerfile --pull=false -q --arch=amd64 -t image-amd --signature-policy /var/tmp/go/src/github.com/containers/buildah/tests/./policy.json /var/tmp/buildah_tests.sufdm8/my-dir
error creating build container: copying system image from manifest list:
     reading signatures:
     parsing signature https://access.redhat.com/webassets/docker/content/sigstore/ubi8-minimal@sha256=SHA/signature-7:
     unrecognized signature format, starting with binary 0x3c

I think this is also the cause of the horrid multiple-platform-no-run flake, or at least one of the causes.

We can't rely on flaky registries. Can all tests that use ubi8-* be fixed to use a different image?

[Integration] 295 bud --pull=false --arch test

• [unknown image] : Integration fedora-35 w/ vfs
  • PR #4111
    • 07-14-2022 12:16
• [unknown image] : Integration rootless fedora-35 w/ overlay
  • PR #4111
    • 07-14-2022 12:19
• [unknown image] : Integration rootless ubuntu-2204 w/ overlay
  • PR #4111
    • 07-14-2022 12:07

[Containerized] 295 bud --pull=false --arch test

• [unknown image] : Containerized Integration
  • PR #4111
    • 07-14-2022 12:04

...and, in podman-land:

[bud] 277 bud --pull=false --arch test

• fedora-36 : bud podman fedora-36 root host
  • PR #16050
    • 10-04 17:51
• fedora-36 : bud remote fedora-36 root host [remote]
  • PR #16050
    • 10-04 17:52

[bud] 268 bud --pull=false --arch test

• fedora-36 : bud podman fedora-36 root host
  • PR #15593
    • 09-06-2022 12:14
  • PR #15285
    • 08-11-2022 09:02
• fedora-36 : bud remote fedora-36 root host [remote]
  • PR #15593
    • 09-06-2022 12:14
  • PR #15285
    • 08-11-2022 08:59

[bud] 261 bud --pull=false --arch test

• fedora-36 : bud podman fedora-36 root host
  • PR #15192
    • 08-04-2022 08:57
• fedora-36 : bud remote fedora-36 root host [remote]
  • PR #15192
    • 08-04-2022 09:01

[edsantiago]

Every. Single. Integration. Job. In. My. PR.

[mtrmac]

For the record: This is the signature server serving 200 OK with HTML content; it is supposed to serve 200 OK with a signature, or 404 — or some non-200 error at least.

[edsantiago]

All CI (buildah and podman), all gating tests, are now broken because ubi8 changed something.

✗ bud --pull=false --arch test
   #/vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
   #|     FAIL: buildah inspect --format {{ index .Docker.Config.Labels "architecture" }} image-arm
   #| expected: =~ 'arm64'
   #|   actual:    'aarch64'
   #\^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When we use images we don't control, on registries we don't control, bad things happen.

[edsantiago]

Fixed in #4384 and #4397.