KVM: selftests: enumerate GUEST_ASSERT arguments

Enumerate GUEST_ASSERT arguments to avoid magic indices to ucall.args.

Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Link: https://lore.kernel.org/r/20220615193116.806312-2-coltonlewis@google.com


Signed-off-by: Sean Christopherson <seanjc@google.com>