Quite a few images are only used a few times in a few tests. Thus,
the images are being centralized into the agnhost image, reducing
the number of images that have to be pulled and used.
This PR replaces the usage of the following images with agnhost:
- fakegitserver
- hostexec
- liveness
- logs-generator
- no-snat-test
- no-snat-test-proxy
- port-forward-tester
Remove SLOW tag and update description for KUBEDESCRIBE(Probing container) and SIGDESCRIBE(EmptyDir Wrapper Volume)
Remove slow references for tests that execute below 5 minutes
Use the same pattern everywhere in the e2e test
harness, use busybox (from dockerhub) instead
of using the one from k8s.gcr.io registry.
Change-Id: I57c3b867408c1f9478a8909c26744ea0368ff003