[turbofan] Introduce DeadValue and DeadEffect operators.

test/unittests/compiler/common-operator-unittest.cc

Index: test/unittests/compiler/common-operator-unittest.cc
diff --git a/test/unittests/compiler/common-operator-unittest.cc b/test/unittests/compiler/common-operator-unittest.cc
index 26e861c1b67684cb7b8fa040318dd1c20c6dd642..973182cb5b202e078ccfe196a53be2e9b75deb7b 100644
--- a/test/unittests/compiler/common-operator-unittest.cc
+++ b/test/unittests/compiler/common-operator-unittest.cc
@@ -48,13 +48,15 @@ const SharedOperator kSharedOperators[] = {
         value_input_count, effect_input_count, control_input_count,          \
         value_output_count, effect_output_count, control_output_count        \
   }
-    SHARED(Dead, Operator::kFoldable, 0, 0, 0, 0, 0, 1),
     SHARED(IfTrue, Operator::kKontrol, 0, 0, 1, 0, 0, 1),
     SHARED(IfFalse, Operator::kKontrol, 0, 0, 1, 0, 0, 1),
     SHARED(IfSuccess, Operator::kKontrol, 0, 0, 1, 0, 0, 1),
     SHARED(Throw, Operator::kKontrol, 1, 1, 1, 0, 0, 1),
     SHARED(Return, Operator::kNoThrow, 1, 1, 1, 0, 0, 1),
-    SHARED(Terminate, Operator::kKontrol, 0, 1, 1, 0, 0, 1)
+    SHARED(Terminate, Operator::kKontrol, 0, 1, 1, 0, 0, 1),
+    SHARED(DeadValue, Operator::kPure, 0, 0, 0, 1, 0, 0),
+    SHARED(DeadEffect, Operator::kPure, 0, 0, 0, 0, 1, 0),
+    SHARED(DeadControl, Operator::kFoldable, 0, 0, 0, 0, 0, 1)
 #undef SHARED
 };