[llvm] [llvm][CodeGen] Fixed max cycle calculation with zero-cost instructions for window scheduler (PR #99454)

[Kai Yan via llvm-commits]

kaiyan96 wrote:

I have split this PR to 4 individual PRs:
* [Added a new restriction for II by pragma](https://github.com/llvm/llvm-project/pull/99448)
* [Added missing initialization failure information](https://github.com/llvm/llvm-project/pull/99449)
* [Fixed a bug in stall cycle calculation](https://github.com/llvm/llvm-project/pull/99451)
* [Fixed max cycle calculation with zero-cost instructions](https://github.com/llvm/llvm-project/pull/99454)

https://github.com/llvm/llvm-project/pull/99454