The build team has published atlas AMIs that we can test on. We want to test as close to production as possible so we would like to start running tests on these variants since they are the same ones that Atlas runs. 

Criteria for switching a task / variant to Atlas AMI:

1. Task/variant is required for server PB, AND
2. Task/variant is not OS-specific (an OS-specific task/variant typically has the OS name in the task/variant name)