[llvm] [DirectX] Set shader feature flags MinimumPrecision and NativeLowPrecision (PR #139623)

[Finn Plummer via llvm-commits]

https://github.com/inbelic requested changes to this pull request.

Hm sorry, I must have been looking at an outdated version of the pull request when reviewing, and didn't see the comments. I will un-approve for now, just ping me directly when it is ready for review with the comments addressed

https://github.com/llvm/llvm-project/pull/139623