This is an IKEv2 test with alias/subnets auto=ondemand on east and crypto delay on west

The CREATE_CHILD_SA retransmit cause the respondert to create multiple Child SA
with same initiator SPI and different responder SPI.

It seems as long as there is only one set(in, out, fwd) policy per tunnel
everything works. Even if there are two tunnels. One initiated by each end.
The corner case seems when there are two sets of policies. Then the traffic flow breaks.