KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD

'run->exit_reason == KVM_EXIT_SHUTDOWN' check is not ideal as we may be
getting some unexpected exception. Directly check for #UD instead.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210505151823.1341678-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>