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

src/contexts.cc

 // Copyright 2011 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/contexts.h"
 
 #include "src/ast/scopeinfo.h"
 #include "src/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 448 matching lines @@
   }
 
   // Check that the context belongs to the weak native contexts list.
   bool found = false;
   Object* context = GetHeap()->native_contexts_list();
   while (!context->IsUndefined()) {
     if (context == this) {
       found = true;
       break;
     }
-    context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
+    context = Context::cast(context)->next_context_link();
   }
   CHECK(found);
 #endif
 
   // If the function link field is already used then the function was
   // enqueued as a code flushing candidate and we remove it now.
   if (!function->next_function_link()->IsUndefined()) {
     CodeFlusher* flusher = GetHeap()->mark_compact_collector()->code_flusher();
     flusher->EvictCandidate(function);
   }
@@ skipping 133 matching lines @@
 
   int previous_value = errors_thrown()->value();
   set_errors_thrown(Smi::FromInt(previous_value + 1));
 }
 
 
 int Context::GetErrorsThrown() { return errors_thrown()->value(); }
 
 }  // namespace internal
 }  // namespace v8