[AA] Updates for D95543.

Addressing latter comments in D95543:
- `AliasResult::Result` renamed to `AliasResult::Kind`
- Offset printing added for `PartialAlias` case in `-aa-eval`
- Removed VisitedPhiBBs check from BasicAA'

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D100454