[llvm] [ADT] Remove unused DenseMapInfo::getEmptyKey (PR #201998)

[Alexis Engelke via llvm-commits]

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@@ -195,11 +162,6 @@ struct DenseMapInfo<Enum, std::enable_if_t<std::is_enum_v<Enum>>> {
   // If you hit this error, you can fix by switching to `enum class`, or adding
   // an explicit underlying type (e.g. `enum X : int`) to the enum's definition.
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aengelke wrote:

Comment obsolete

https://github.com/llvm/llvm-project/pull/201998