Move DeadControl into the JSGraph so that it can be reused.

src/compiler/js-graph.h

Index: src/compiler/js-graph.h
diff --git a/src/compiler/js-graph.h b/src/compiler/js-graph.h
index 761b0dffe1bc6dd4ebee68ad9206d4fef464bdbc..fe9b9f7b7ccdd0aa8e7e436128c64a3ea1d399f5 100644
--- a/src/compiler/js-graph.h
+++ b/src/compiler/js-graph.h
@@ -114,6 +114,9 @@ class JSGraph : public ZoneObject {
   // cannot deopt.
   Node* EmptyFrameState();
 
+  // Create a control node that serves as control dependency for dead nodes.
+  Node* DeadControl();
+
   JSOperatorBuilder* javascript() const { return javascript_; }
   CommonOperatorBuilder* common() const { return common_; }
   MachineOperatorBuilder* machine() const { return machine_; }
@@ -142,6 +145,7 @@ class JSGraph : public ZoneObject {
   SetOncePointer<Node> one_constant_;
   SetOncePointer<Node> nan_constant_;
   SetOncePointer<Node> empty_frame_state_;
+  SetOncePointer<Node> dead_control_;
 
   CommonNodeCache cache_;