[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..ccea222fa45fc27594fd309de43ef15936ed2e2d 100644
--- a/test/unittests/compiler/common-operator-unittest.cc
+++ b/test/unittests/compiler/common-operator-unittest.cc
@@ -49,6 +49,8 @@ const SharedOperator kSharedOperators[] = {
         value_output_count, effect_output_count, control_output_count        \
   }
     SHARED(Dead, Operator::kFoldable, 0, 0, 0, 0, 0, 1),
+    SHARED(DeadValue, Operator::kPure, 0, 0, 0, 1, 0, 0),
+    SHARED(DeadEffect, Operator::kPure, 0, 0, 0, 0, 1, 0),
     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),