Slang - test with latest spirv header and ensure it's good for inclusion in the sdk release by feb 28

[bmillsNV]

after we ensure - we need to provide the verified commit id to lunarg for inclusion in the march 11 SDK.

[expipiplus1]

I've made a draft release https://github.com/shader-slang/slang/releases/tag/v2025.5.4-draft) from the main branch which has confirmed that there are no regressions from bumping to the latest glslang, spirv-tools, spirv-headers. Just for good measure I also tested that there are no regressions with the vulkan-tmp-1.4.309 tag of glslang and associated known_good versions of spirv-headers and spirv-tools.

As for why it's just a draft release:There is a test failure on aarch64 (seems to be transient, and not to do with the version bump), hence the draft release. This issue tracks that test failure, #6481. I think that this test failure is niche enough that it's probably ok to just cut a release and maybe mention this in the errata.

[expipiplus1]

2025.6.1 should demonstrate the good revisions