test cleanup
test cleanup

 - remove a bunch of unnecessary clutter (checking $status)
 - add distinct labels to similar-looking tests
 - add check for cpp warning
 - split Containerfile.in test into two parts, one with command-line
   flag and one with envariable, so podman can skip the latter
   in -remote tests while testing the former

Signed-off-by: Ed Santiago <792d28329de7ed446c01b83f731a071248ffeaf4@redhat.com>

TomSweeneyRedHat/buildah,TomSweeneyRedHat/buildah,TomSweeneyRedHat/buildah,nalind/buildah-1,nalind/buildah-1,nalind/buildah-1