Added some functionality tests for CFL AA, and made a minor fix to CFL AA
- CFL AA fix: We used to return PartialAlias if *either* variable being queried interacted with arguments or globals. AFAICT, we can change this to only returning PartialAlias iff *both* variables being queried interacted with arguments or globals.
- Functionality tests: some basic IPA tests, checking that we give conservative responses with arguments/globals thrown in the mix, and ensuring that we trace values through stores and loads.
x interacted with arguments or globals = the Attributes of the StratifiedSet that x belongs to has any bits set.