Split function block scoping into a separate flag

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 91e37912d163926131607322f3f1064b8c13b017..db9bb68e8665861baac6a77bf458526ec3ef4b1f 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -109,6 +109,7 @@ class ParserBase : public Traits {
         allow_lazy_(false),
         allow_natives_(false),
         allow_harmony_arrow_functions_(false),
+        allow_harmony_block_function_(false),
         allow_harmony_sloppy_(false),
         allow_harmony_sloppy_let_(false),
         allow_harmony_rest_parameters_(false),
@@ -126,6 +127,7 @@ class ParserBase : public Traits {
   ALLOW_ACCESSORS(lazy);
   ALLOW_ACCESSORS(natives);
   ALLOW_ACCESSORS(harmony_arrow_functions);
+  ALLOW_ACCESSORS(harmony_block_function);
   ALLOW_ACCESSORS(harmony_sloppy);
   ALLOW_ACCESSORS(harmony_sloppy_let);
   ALLOW_ACCESSORS(harmony_rest_parameters);
@@ -799,6 +801,7 @@ class ParserBase : public Traits {
   bool allow_lazy_;
   bool allow_natives_;
   bool allow_harmony_arrow_functions_;
+  bool allow_harmony_block_function_;
   bool allow_harmony_sloppy_;
   bool allow_harmony_sloppy_let_;
   bool allow_harmony_rest_parameters_;