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

src/ia32/assembler-ia32.cc

Index: src/ia32/assembler-ia32.cc
diff --git a/src/ia32/assembler-ia32.cc b/src/ia32/assembler-ia32.cc
index 435b64d5b9cd31106ae551e350e66a074d793bfa..e53165142bda9b5f1f3c6cfd9db2dc983e001fd7 100644
--- a/src/ia32/assembler-ia32.cc
+++ b/src/ia32/assembler-ia32.cc
@@ -129,7 +129,8 @@ void CpuFeatures::Probe(bool portable) {
   }
   if (!code->IsCode()) return;
 
-  PROFILE(CodeCreateEvent(Logger::BUILTIN_TAG,
+  PROFILE(ISOLATE,
+          CodeCreateEvent(Logger::BUILTIN_TAG,
                           Code::cast(code), "CpuFeatures::Probe"));
   typedef uint64_t (*F0)();
   F0 probe = FUNCTION_CAST<F0>(Code::cast(code)->entry());