Canonicalize handles for optimized compilation.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index aeaf82ed829f5525edc4384f3bd361d307177876..f50c2fad876a7c8898ce1dc56451166e73815dd6 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1874,8 +1874,6 @@ void Isolate::ClearSerializerData() {
   external_reference_table_ = NULL;
   delete external_reference_map_;
   external_reference_map_ = NULL;
-  delete root_index_map_;
-  root_index_map_ = NULL;
 }
 
 
@@ -1935,6 +1933,9 @@ void Isolate::Deinit() {
   delete cpu_profiler_;
   cpu_profiler_ = NULL;
 
+  delete root_index_map_;
+  root_index_map_ = NULL;
+
   ClearSerializerData();
 }