[llvm] [mlir] [mlir][spirv] Integrate `convert-to-spirv` into `mlir-vulkan-runner` (PR #106082)

[Jakub Kuderski via llvm-commits]

https://github.com/kuhar commented:

Could we add a couple of LIt tests for this? Right now the testing depends on the mlir runner, but most folks probably have it disabled and only run cpu tests in their daily development flow.

https://github.com/llvm/llvm-project/pull/106082