[turbofan] Introduce DeadValue and DeadEffect operators.

src/compiler/common-operator.h

Index: src/compiler/common-operator.h
diff --git a/src/compiler/common-operator.h b/src/compiler/common-operator.h
index 08553bceaa6ec7650d4ba96318c1c87f976f7a56..c3decbd82d71f7f8cca73b9394432a359484fef5 100644
--- a/src/compiler/common-operator.h
+++ b/src/compiler/common-operator.h
@@ -96,7 +96,6 @@ class CommonOperatorBuilder final : public ZoneObject {
  public:
   explicit CommonOperatorBuilder(Zone* zone);
 
-  const Operator* Dead();
   const Operator* End(size_t control_input_count);
   const Operator* Branch(BranchHint = BranchHint::kNone);
   const Operator* IfTrue();
@@ -111,6 +110,10 @@ class CommonOperatorBuilder final : public ZoneObject {
   const Operator* Return();
   const Operator* Terminate();
 
+  const Operator* Dead();
+  const Operator* DeadValue();
+  const Operator* DeadEffect();
+
   const Operator* Start(int num_formal_parameters);
   const Operator* Loop(int control_input_count);
   const Operator* Merge(int control_input_count);