[llvm] [ConstantHoisting] Add a TTI hook to prevent hoisting. (PR #69004)

[Nikita Popov via llvm-commits]

nikic wrote:

@sjoerdmeijer ConstaintHoisting is a backend pass, so it's fine to restrict it based on target-specific heuristics (in fact, the entire pass is already TTI-driven).

https://github.com/llvm/llvm-project/pull/69004