qemuxml2(argv|xml)test: Unify usage of DO_TEST_CAPS_LATEST

The qemuxml2argv invocation of some tests used DO_TEST_CAPS_LATEST while
the qemuxml2xmltest invocation uses fake caps. Unify them on
DO_TEST_CAPS_LATEST.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

tests/qemuxml2argvdata/memfd-memory-numa.xml

@@ -20,7 +20,8 @@
     <type arch='x86_64' machine='pc-i440fx-2.3'>hvm</type>
     <boot dev='hd'/>
   </os>
-  <cpu>
+  <cpu mode='custom' match='exact' check='none'>
+    <model fallback='forbid'>qemu64</model>
     <topology sockets='1' dies='1' cores='8' threads='1'/>
     <numa>
       <cell id='0' cpus='0-7' memory='14680064' unit='KiB'/>
@@ -32,7 +33,7 @@
   <on_crash>destroy</on_crash>
   <devices>
     <emulator>/usr/bin/qemu-system-x86_64</emulator>
-    <controller type='usb' index='0'>
+    <controller type='usb' index='0' model='piix3-uhci'>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
     </controller>
     <controller type='pci' index='0' model='pci-root'/>