[llvm] [HLSL] Fix Root signature test error (PR #127261)

[Justin Bogner via llvm-commits]

bogner wrote:

I don't think this is correct. It looks to me like this is printing the root signature flags in a non-deterministic order.

 The problem is that we're iterating over a map in RootSignatureAnalysisPrinter - this isn't guaranteed any particular order. Instead, we should iterate over the functions in the module and look them up in the map.

https://github.com/llvm/llvm-project/pull/127261