Add tests to testing HVM default features (pae, acpi, apic)
conversion from xm config to libvirt xml. If no pae|acpi|apic
specified in xm config, after conversion, libvirt xml should
by default include:
<features>
<pae/>
<apic/>
<acpi/>
</features>
Signed-off-by: Chunyan Liu <cyliu@suse.com>
