Add tool to visualize machine code/lithium.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 9fb8307983d2d4e6b894ac4873f751228b1dc8ef..d9dd8d53844f4d887e7ee18d7f53c4fc9d2c6b14 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -665,7 +665,7 @@ LInstruction* LChunkBuilder::MarkAsCall(LInstruction* instr,
 
 LInstruction* LChunkBuilder::AssignPointerMap(LInstruction* instr) {
   ASSERT(!instr->HasPointerMap());
-  instr->set_pointer_map(new(zone()) LPointerMap(position_, zone()));
+  instr->set_pointer_map(new(zone()) LPointerMap(zone()));
   return instr;
 }
 
@@ -859,7 +859,6 @@ void LChunkBuilder::DoBasicBlock(HBasicBlock* block, HBasicBlock* next_block) {
 void LChunkBuilder::VisitInstruction(HInstruction* current) {
   HInstruction* old_current = current_instruction_;
   current_instruction_ = current;
-  if (current->has_position()) position_ = current->position();
 
   LInstruction* instr = NULL;
   if (current->CanReplaceWithDummyUses()) {
@@ -914,7 +913,6 @@ void LChunkBuilder::VisitInstruction(HInstruction* current) {
     }
 #endif
 
-    instr->set_position(position_);
     if (FLAG_stress_pointer_maps && !instr->HasPointerMap()) {
       instr = AssignPointerMap(instr);
     }