eni/tests: provide test defaults for AZ and VPC
eni/tests: provide test defaults for AZ and VPC

Since none of the tests ever set anything other than AZ us-west-1 and
VPC vpc-1, provide these values as withTestDefaults for brevity.

Signed-off-by: David Bimmler <2b9100fd3561bfd5a02ba57997321a6951c1225e@isovalent.com>

cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium