[llvm] [CodeGen][Transforms] Remove unused DenseMapInfo::getEmptyKey (PR #201994)

[Fangrui Song via llvm-commits]

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@@ -463,9 +457,6 @@ template <>
 struct DenseMapInfo<const AA::InstExclusionSetTy *>
     : public DenseMapInfo<void *> {
   using super = DenseMapInfo<void *>;
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MaskRay wrote:

removed

https://github.com/llvm/llvm-project/pull/201994