tests: Drop qemuxml2argv- prefix for qemuxml2argv-*.xml test cases

These XMLs live in a separate directory, there's no need for them
to have a special prefix in addition. It also doesn't play nicely
with ':e' completion in Vim, finding proper file based on
qemuxml2argvtest.c is also needlessly complicated.

The files were renamed using the following commands. From
qemuxml2argvdata:

  for i in qemuxml2argv-*.xml; do mv $i ${i#qemuxml2argv-}; done

and then (to fix broken symlinks) from qemuxml2argvdata and
qemuxml2xmloutdata:

  for i in $(find . -xtype l); do \
      ln -sf $(readlink $i | sed 's/qemuxml2argv-//') $i;
  done

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

tests/qemuxml2argvdata/pseries-basic.xml

@@ -0,0 +1,17 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>1ccfd97d-5eb4-478a-bbe6-88d254c16db7</uuid>
+  <memory unit='KiB'>524288</memory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='ppc64' machine='pseries'>hvm</type>
+  </os>
+  <clock offset='utc'/>
+  <devices>
+    <emulator>/usr/bin/qemu-system-ppc64</emulator>
+    <console type='pty'>
+      <address type="spapr-vio"/>
+    </console>
+    <memballoon model="none"/>
+  </devices>
+</domain>