Add "isolate" argument to LOG macro to avoid TLS fetches.

src/handles.h

 // Copyright 2006-2008 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 116 matching lines @@
   static Address current_limit_address();
   static Address current_level_address();
 
   // Closes the HandleScope (invalidating all handles
   // created in the scope of the HandleScope) and returns
   // a Handle backed by the parent scope holding the
   // value of the argument handle.
   template <typename T>
   Handle<T> CloseAndEscape(Handle<T> handle_value);
 
+  Isolate* isolate() { return isolate_; }
+
  private:
   // Prevent heap allocation or illegal handle scopes.
   HandleScope(const HandleScope&);
   void operator=(const HandleScope&);
   void* operator new(size_t size);
   void operator delete(void* size_t);
 
   inline void CloseScope();
 
   Isolate* isolate_;
@@ skipping 232 matching lines @@
  private:
   bool has_been_transformed_;  // Tells whether the object has been transformed.
   int unused_property_fields_;  // Captures the unused number of field.
   Handle<JSObject> object_;    // The object being optimized.
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_