test-cutils: Add more coverage to qemu_strtosz Add some more strings that the user might send our way. In particular, some of these additions include FIXME comments showing where our parser doesn't quite behave the way we want. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20230522190441.64278-15-eblake@redhat.com>