qemumonitorjsontest: Validate more commands against schema

The DO_TEST() macro in qemumonitorjsontest.c was not passing the
schema through, which meant that we were not validating any of those
tests for correct usage according to the schema.

In the process of mechanically altering tests to pass the schema
through, use VIR_AUTOPTR on all of the affected test instances. The
next patch will do some further cleanups that it exposes.

Tested by using this hack, where the test mistakenly passed pre-patch,
but correctly diagnosed the garbage post-patch:

| diff --git i/src/qemu/qemu_monitor_json.c w/src/qemu/qemu_monitor_json.c
| index 53a7de8b77..86d8450814 100644
| --- i/src/qemu/qemu_monitor_json.c
| +++ w/src/qemu/qemu_monitor_json.c
| @@ -1532,7 +1532,8 @@ qemuMonitorJSONGetStatus(qemuMonitorPtr mon,
|      if (reason)
|          *reason = VIR_DOMAIN_PAUSED_UNKNOWN;
|
| -    if (!(cmd = qemuMonitorJSONMakeCommand("query-status", NULL)))
| +    if (!(cmd = qemuMonitorJSONMakeCommand("query-status",
| +                                           "s:garbage", "foo", NULL)))
|          return -1;
|
|      if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
Suggested-by: NPeter Krempa <pkrempa@redhat.com>
Signed-off-by: NEric Blake <eblake@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>