IKEv2 with two template conns; each has different rightsubnet=; leftsubnet= is unset.

both should establish

Unlike ikev2-connswitch-06-dual-net-net, which has explicitly
identical leftsubnet=, this test's leftsubnet= is identical implicitly
- because it defaults to ${left}/32.

The first connection will guess correctly during IKE_SA_INIT.

The second connection will guess wrong, and then need to switch to and
instantiate the second connection.

The bug is because the code matching the template needs to account for
an implicit leftsubnet=${left}/32.

this is https://github.com/libreswan/libreswan/issues/2380
see also https://github.com/libreswan/libreswan/issues/275
