Handle dereferencing needs to be allowed for printing during optimization phase.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 204ec20adb8c2d3ff358e37d008625dc5829a1fa..5aa6e05409338f463da0375ed041c19d81cc2aa5 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -10788,6 +10788,7 @@ void HPhase::End() const {
   // phase name matches the command line parameter FLAG_trace_phase.
   if (FLAG_trace_hydrogen &&
       OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL) {
+    AllowHandleDereference allow_handle_deref(graph_->isolate());
     if (graph_ != NULL) HTracer::Instance()->TraceHydrogen(name_, graph_);
     if (chunk_ != NULL) HTracer::Instance()->TraceLithium(name_, chunk_);
     if (allocator_ != NULL) {