[llvm-branch-commits] [AllocToken] Make token mode a pass parameter (PR #163634)

[Marco Elver via llvm-branch-commits]

https://github.com/melver created https://github.com/llvm/llvm-project/pull/163634

This change refactors the AllocToken pass to accept the mode via pass options
rather than LLVM cl::opt. This is both cleaner, but also required to make the
mode frontend-driven and avoid potential inconsistencies.