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

src/platform-freebsd.cc

Index: src/platform-freebsd.cc
diff --git a/src/platform-freebsd.cc b/src/platform-freebsd.cc
index 9c3f295ecfa6d778ec3c5fb1659313a4dc70d96c..64116db48fdd0a1ccecd8f290b91365a97770c5b 100644
--- a/src/platform-freebsd.cc
+++ b/src/platform-freebsd.cc
@@ -155,7 +155,7 @@ void* OS::Allocate(const size_t requested,
   void* mbase = mmap(NULL, msize, prot, MAP_PRIVATE | MAP_ANON, -1, 0);
 
   if (mbase == MAP_FAILED) {
-    LOG(StringEvent("OS::Allocate", "mmap failed"));
+    LOG(ISOLATE,StringEvent("OS::Allocate", "mmap failed"));
     return NULL;
   }
   *allocated = msize;