numatune: Add tests for numatune XML

Only add tests for qemuxmlargvtest.c, as there is no qemu command line
for numatune XML, just want to make sure the XML could be validated
well.

tests/qemuxml2argvdata/qemuxml2argv-numatune-memory.args

+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M \
+pc -m 214 -smp 2 -nographic -monitor \
+unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -hda \
+/dev/HostVG/QEMUGuest1 -net none -serial none -parallel none -usb

tests/qemuxml2argvdata/qemuxml2argv-numatune-memory.xml

+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory>219136</memory>
+  <currentMemory>219136</currentMemory>
+  <vcpu>2</vcpu>
+  <numatune>
+    <memory mode="strict" nodeset="0-5,^4"/>
+  </numatune>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <cpu>
+    <topology sockets='2' cores='1' threads='1'/>
+  </cpu>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' unit='0'/>
+    </disk>
+    <controller type='ide' index='0'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -519,6 +519,7 @@ mymain(void)
     DO_TEST("memtune", false, QEMU_CAPS_NAME);
     DO_TEST("blkiotune", false, QEMU_CAPS_NAME);
     DO_TEST("cputune", false, QEMU_CAPS_NAME);
+    DO_TEST("numatune-memory", false, NONE);
 
     DO_TEST("multifunction-pci-device", false,
             QEMU_CAPS_DRIVE, QEMU_CAPS_DEVICE, QEMU_CAPS_NODEFCONFIG,