[llvm] [VPlan] Use BlockFrequencyInfo in getPredBlockCostDivisor (PR #158690)

[Luke Lau via llvm-commits]

lukel97 wrote:

> @lukel97 We are seeing a crash compiling a rocm library with this change.
> 
> Reduced ll and script: [reproducer.zip](https://github.com/user-attachments/files/24044814/reproducer.zip)

Looks like we're truncating a double to unsigned which causes a divide by zero. Will push a fix soon. 

https://github.com/llvm/llvm-project/pull/158690