[llvm] [llvm] Lower latency bonus threshold in function specialization. (PR #143954)

[Alexandros Lamprineas via llvm-commits]

labrinea wrote:

At first I thought that a 20% latency threshold is too low, but Nikita's comment seems reassuring. Looking at the related issue https://github.com/llvm/llvm-project/issues/143219 I am seeing that  `digits_2` needs 34%, is that right? Do we perhaps prefer a higher number like 30%, or is it likely that will need to decrease it again in the future? Out of curiosity, what is the compile time impact if we completely disregard this metric (MinLatencySavings = 0) ? 

https://github.com/llvm/llvm-project/pull/143954