* aws_vpc_subnet: (integration tests) migrate to module_defaults
* aws_vpc_subnet: (integration tests) remove hard coded assumption that AZ A exists.
While Amazon now tends to enable all AZs in a region, new customers in us-west-1 are only assigned 2 out of the 3 AZs, which might not include AZ a
* ec2_vpc_subnet: (integration tests) General cleanup
- use "is changed" rather than .changed
- clean up labelling of a couple of assertions (C&P fail)
cbe511de1f