[clang] [llvm] [NFC][HLSL][RootSignature] Split up `HLSLRootSignatureUtils` (PR #146124)

[Finn Plummer via llvm-commits]

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@@ -103,7 +51,7 @@ class ResourceRange {
   getOverlapping(const RangeInfo &Info) const;
 
   // Return the mapped RangeInfo at X or nullptr if no mapping exists
-  LLVM_ABI const RangeInfo *lookup(uint32_t X) const;
+  const RangeInfo *lookup(uint32_t X) const;
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inbelic wrote:

```suggestion
  LLVM_ABI const RangeInfo *lookup(uint32_t X) const;
```

https://github.com/llvm/llvm-project/pull/146124