When we unconditionally enable QEMU_CAPS_DEVICE, these tests need
some massaging, so do it ahead of time to not mix it in with the
big test refresh.
- minimal-s390 is not a real world working config, so drop it
- disk-usb was testing for an old code path that will be removed.
instead use it to test lack of USB disk support, and rename it
to disk-usb-nosupport. Switch xml2xml to use disk-usb-device for
input.
- cputune-numatune was needlessly using q35, switch it to an older
machine type
