Adding 'isolates' argument to LOG to get rid of multiple TLS fetches in profiling.

src/log.h

Index: src/log.h
diff --git a/src/log.h b/src/log.h
index 1d7daeabd0cb10a93a058c6020d62c55d968e93a..66083de31f2755dede626aa40b1d86a6fd3ce974 100644
--- a/src/log.h
+++ b/src/log.h
@@ -78,15 +78,15 @@ class LogMessageBuilder;
 #undef LOG
 // TODO(isolates): pass isolate pointer here.
 #ifdef ENABLE_LOGGING_AND_PROFILING
-#define LOG(Call)                                   \
+#define LOG(isolate,Call)                           \
   do {                                              \
     v8::internal::Logger* logger =                  \
-        v8::internal::Isolate::Current()->logger(); \
+        (isolate)->logger();                        \
     if (logger->is_logging())                       \
       logger->Call;                                 \
   } while (false)
 #else
-#define LOG(Call) ((void) 0)
+#define LOG(isolate,Call) ((void) 0)
 #endif
 
 #define LOG_EVENTS_AND_TAGS_LIST(V) \