tests: qemucaps: Add QMP introspection data for qemu 2.6.0 on aarch64 gicv3

Add QMP schema data query for aarch64. The gic capabilities are
unfortunately queried after the QMP schema and thus this patch needs to
undo the temporary removal of the declared support for query-qmp-schema.

Note that as a gicv3 machine was not available the schema data is taken
from the gicv2 case. It should be identical since qemu would be built
from the same source.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

tests/qemucapabilitiesdata/caps_2.6.0-gicv3.aarch64.xml

@@ -161,6 +161,7 @@
   <flag name='drive-iotune-max-length'/>
   <flag name='ivshmem-plain'/>
   <flag name='ivshmem-doorbell'/>
+  <flag name='query-qmp-schema'/>
   <version>2005094</version>
   <kvmVersion>0</kvmVersion>
   <package></package>