[llvm] [NFC] Remove isRequired() from analyses (PR #196121)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

The AssignmentTracking one is more weird given it's in a LegacyPM `FunctionPass`, so makes even more sense to get rid of.

LGTM.

https://github.com/llvm/llvm-project/pull/196121