Currently, when generating tasks in Evergreen for parallelizing the suite, the code assumes that only a single test suite is being targeted. However, it looks more likely that we will need to support generating more than 1 test suite in a single pass. Doing some initial refactoring would make this support much easier to add.

As a DAG engineer,
I want the generate tasks code to support generating multiple tasks,
So that I can easily changes to different approaches to task generation.