Testing various configuration schemas targeting postive and negative
nestedhvm under libvirt <cpu mode="host-passthrough"> configuration.

Mode "host-passthrough" generates nestedhvm=1 in/from xl format where

Intel virtualization (VT-x):
<feature policy='disable' name='vmx'/>

    or

AMD virtualization (AMD-V):
<feature policy='disable' name='svm'/>

disables virtualization mode under guest domains.
Signed-off-by: NWim ten Have <wim.ten.have@oracle.com>
Signed-off-by: NJim Fehlig <jfehlig@suse.com>