[llvm] [SandboxIR] Implement ConstantTokenNone (PR #108106)

[Sriraman Tallam via llvm-commits]

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@@ -1141,6 +1142,36 @@ class BlockAddress final : public Constant {
   }
 };
 
+class ConstantTokenNone final : public Constant {
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tmsri wrote:

TODO: Inherit from ConstantData when that becomes available

https://github.com/llvm/llvm-project/pull/108106