[turbofan] Introduce DeadValue and DeadEffect operators.

src/compiler/js-graph.cc

Index: src/compiler/js-graph.cc
diff --git a/src/compiler/js-graph.cc b/src/compiler/js-graph.cc
index 35984b8357b08a6aa5f2c88958605922aee06d43..10e20a1bd5f772e0377541f9b13ee5098392f5d8 100644
--- a/src/compiler/js-graph.cc
+++ b/src/compiler/js-graph.cc
@@ -203,8 +203,13 @@ Node* JSGraph::EmptyFrameState() {
 }
 
 
+Node* JSGraph::DeadValue() {
+  return CACHED(kDeadValue, graph()->NewNode(common()->DeadValue()));
+}
+
+
 Node* JSGraph::DeadControl() {
-  return CACHED(kDeadControl, graph()->NewNode(common()->Dead()));
+  return CACHED(kDeadControl, graph()->NewNode(common()->DeadControl()));
 }