Same as ikev2-03-basic-rawrsa, but now pluto on east is forced to be "busy" using
the ddos-mode=busy option, simulating a Denial of Service attack.

east will return the packet with a request for a dcookie without creating
a new state. west needs to send a new I1 that includes the dcookie payload
and east will then create a new state object and continue as normal.

This is also known as the "6 message Exchange"