[llvm] [DirectX] adding support in obj2yaml and yaml2obj to root constants (PR #127840)

[Chris B via llvm-commits]

================
@@ -14,20 +14,18 @@ Parts:
     Size:            24
     RootSignature:
       Version: 2
-      NumParameters: 1
-      RootParametersOffset: 3
       NumStaticSamplers: 4
       StaticSamplersOffset: 5
+      Parameters: []
       AllowInputAssemblerInputLayout: true
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llvm-beanz wrote:

If you remove the ability to express the offsets in the YAML, you'll need to make sure to update the unit test cases with additional hex-encoded tests to cover all the edge conditions where the offsets may be incorrect.

https://github.com/llvm/llvm-project/pull/127840