[llvm-branch-commits] [ThinLTO] Mark AssignGUIDPass as RequiredPassInfoMixin (PR #211987)

[Aiden Grossman via llvm-branch-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/211987

PassInfoMixin is going away, so switch to RequiredPassInfoMixin and
remove the explicit isRequired implementation.