Fix arm port of tracking field representations. Based on Rodolph Perfetta's comments

src/arm/lithium-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2102 matching lines @@
     context = UseRegister(instr->context());
     value = UseRegister(instr->value());
   }
   LInstruction* result = new(zone()) LStoreContextSlot(context, value);
   return instr->RequiresHoleCheck() ? AssignEnvironment(result) : result;
 }
 
 
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
   LOperand* obj = UseRegisterAtStart(instr->object());
-  LOperand* temp = instr->representation().IsDouble() ? TempRegister() : NULL;
-  ASSERT(temp == NULL || FLAG_track_double_fields);
-  return DefineAsRegister(new(zone()) LLoadNamedField(obj, temp));
+  return DefineAsRegister(new(zone()) LLoadNamedField(obj));
 }
 
 
 LInstruction* LChunkBuilder::DoLoadNamedFieldPolymorphic(
     HLoadNamedFieldPolymorphic* instr) {
   ASSERT(instr->representation().IsTagged());
   if (instr->need_generic()) {
     LOperand* obj = UseFixed(instr->object(), r0);
     LLoadNamedFieldPolymorphic* result =
         new(zone()) LLoadNamedFieldPolymorphic(obj);
@@ skipping 493 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal