[runtime] Avoid @@isConcatSpreadable lookup for fast path Array.prototype.concat

src/context-measure.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/context-measure.h"
 
 #include "src/base/logging.h"
 #include "src/contexts.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
 
 ContextMeasure::ContextMeasure(Context* context)
     : context_(context),
       root_index_map_(context->GetIsolate()),
       recursion_depth_(0),
       count_(0),
       size_(0) {
   DCHECK(context_->IsNativeContext());
-  Object* next_link = context_->get(Context::NEXT_CONTEXT_LINK);
+  Object* next_link = context_->next_context_link();
   MeasureObject(context_);
   MeasureDeferredObjects();
   context_->set(Context::NEXT_CONTEXT_LINK, next_link);
 }
 
 
 bool ContextMeasure::IsShared(HeapObject* object) {
   if (object->IsScript()) return true;
   if (object->IsSharedFunctionInfo()) return true;
   if (object->IsScopeInfo()) return true;
@@ skipping 37 matching lines @@
 
 
 void ContextMeasure::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     if ((*current)->IsSmi()) continue;
     MeasureObject(HeapObject::cast(*current));
   }
 }
 }  // namespace internal
 }  // namespace v8