tests/qapi-schema: Drop simple union __org.qemu_x-Union1

Replace simple union __org.qemu_x-Union1 with flat union
__org.qemu_x-Union2, except drop it from __org.qemu_x-command, because
there it's only used to pull it into QMP.  Now drop the unused
-Union1, and rename -Union2 to -Union.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210917143134.412106-20-armbru@redhat.com>
3 files changed