Exclude tinycore tests from s390x e2e test suite

[cfilleke]

Is your feature request related to a problem? Please describe:
When running s390x e2e tests, uses tinycore image which is not supported on s390x

Describe the solution you'd like:
label tinycore tests so we can exclude them explicitly from s390x e2e test suite

Describe alternatives you've considered:
currently we use a work-around which is to use a regex in the manual ginkgo test call to exclude tinycore image; it's preferable to have it explicitly labelled; considered building tinycore image for s390x but that would be a bigger and external project with more permissions required.

Additional context:
only applies to s390x architecture.

[akalenyu]

uses tinycore image which is not supported on s390x

not sure what that means? there are no VMs created in CDI tests so any image should work just fine

[awels]

Right on the CDI side we are only interested in the bytes being written from the source to the target. We don't even know about VMs or what they are in CDI. If there are failures on s390x in the CDI test suite there is some other reason.

[cfilleke]

The tests were balking at using the image provided, but it looks like @Davo911 has built an image that the s390x CDI will recognize and move around now -- he's trying to get it to start up busybox or get a shell running in it (since it's just the kernel plus some basic tools at its simplest) anyway. But yah we could use an s390x formatted VM for the tests that are there now, even if it doesn't boot or bring up a shell.