tests: Update *-headless and *-graphics

tests: Update *-headless and *-graphics

Use the latest virt-manager to regenerate the files.

The command line is once again along the lines of

  $ virt-install \
    --name guest --os-variant fedora29 \
    --vcpus 4 --memory 4096 --disk size=5 \
    --graphics (none|vnc) \
    --print-xml

with some minor tweaks performed afterwards.

This removes a number of inconsistencies between the files,
and makes it so the only differences are actually relevant
either to the architecture and machine type at hand, or to
having graphics rather than being headless.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>