[llvm] [llvm][CodeGen] Address the issue of multiple resource reservations in window scheduling (PR #100301)

[Kai Yan via llvm-commits]

kaiyan96 wrote:

> Before this patch:
<img width="907" alt="image" src="https://github.com/user-attachments/assets/6a3acdde-d577-434d-a2b9-98ebb7be3b54">
* We observe that `V6_vaddw` fails to emit all three instructions in parallel if the window scheduler runs `reserveResources` multiple times.
> After this patch:
<img width="906" alt="image" src="https://github.com/user-attachments/assets/37cf6991-2dd5-496c-a13f-873566b37711">
* Now, all three `V6_vaddw` can be emit in the same cycle.


https://github.com/llvm/llvm-project/pull/100301