conformance tests: use mirror.gcr.io for most images

[nalind]

What type of PR is this?

/kind failing-test

What this PR does / why we need it:

Use busybox and alpine images from mirror.gcr.io, where possible, to avoid tripping pull limits in CI.

How to verify it

So many updated conformance tests!

Which issue(s) this PR fixes:

None

Special notes for your reviewer:

Does this PR introduce a user-facing change?

None

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nalind

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [nalind]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[TomSweeneyRedHat]

LGTM
@edsantiago if you can give this a quick looksee, I'd appreciate it.

[edsantiago]

I'm confused. There's already a registries.conf that fixes this. Is it not fixing it? What problem are we seeing?

[edsantiago]

hold on, I merged local-registry in #5584. We should absolutely not be using any network pulls any more! What's happening?

[nalind]

Conformance tests use docker build with the docker daemon and friends as the baseline, and they don't pay attention to registries.conf. In order to use the same base images, the code paths that use buildah can't either.

[nalind]

Well, not docker build per se, but the REST API that the docker engine provides.

[rhatdan]

/lgtm