Add tool to visualize machine code/lithium.

src/lithium.h

Index: src/lithium.h
diff --git a/src/lithium.h b/src/lithium.h
index fd50ee8f8b9df0f20d5b5ac70682ca5d633b6177..4f84087835ae9a24dd33fccdcec8f1ff5b9f13ec 100644
--- a/src/lithium.h
+++ b/src/lithium.h
@@ -476,10 +476,9 @@ class LParallelMove V8_FINAL : public ZoneObject {
 
 class LPointerMap V8_FINAL : public ZoneObject {
  public:
-  explicit LPointerMap(int position, Zone* zone)
+  explicit LPointerMap(Zone* zone)
       : pointer_operands_(8, zone),
         untagged_operands_(0, zone),
-        position_(position),
         lithium_position_(-1) { }
 
   const ZoneList<LOperand*>* GetNormalizedOperands() {
@@ -489,7 +488,6 @@ class LPointerMap V8_FINAL : public ZoneObject {
     untagged_operands_.Clear();
     return &pointer_operands_;
   }
-  int position() const { return position_; }
   int lithium_position() const { return lithium_position_; }
 
   void set_lithium_position(int pos) {
@@ -505,7 +503,6 @@ class LPointerMap V8_FINAL : public ZoneObject {
  private:
   ZoneList<LOperand*> pointer_operands_;
   ZoneList<LOperand*> untagged_operands_;
-  int position_;
   int lithium_position_;
 };