vulkan: RDNA3/4 Large-Tile Split-K Optimization (#30280)
* RDNA3/4 Vulkan Large-Tile Split-K Optimization
* Add single-operator performance test cases
* Update the policy to use driver-reported LDS usage
* Add comments
* Use the simpler split_k rule from review
Assisted-by: GitHub Copilot
* tests : drop the split_k test cases
* vulkan : simplify the RDNA3/4 split_k condition
