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

[Sjoerd Meijer via llvm-commits]

sjoerdmeijer wrote:

I understood that hoisting and LICM were considered canonicalisation passes/transforms in LLVM. I have seen many attempts to restrict hoisting for one reason or another but I have seen them always being rejected because of the canonicalisation argument. Not sure this case is different, but perhaps @nikic who replied here can comment on that. 

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