Update Cloud Hypervisor test(s) to use initrd

[jodh-intel]

Once kata-containers/kata-containers#3567 lands, we can change atleast one (but not all) of the Cloud Hypervisor tests to use an initrd= rather than an image= to ensure this feature is tested.

The test to change looks like this one:

• https://github.com/kata-containers/tests/blob/main/integration/kubernetes/vfio.sh#L193..L202

Related: kata-containers/kata-containers#900

Any thoughts on this @devimc, @likebreath, @GabyCT?

[GabyCT]

/cc @jcvenegas who is the maintainer of the CLH CI

[GabyCT]

@jodh-intel is this still relevant? this is related with kata-containers/ci#476, we will need a maintainer for that

[jodh-intel]

@GabyCT - I think it is, but @fidencio may have further input here.