[es6] ship @@toStringTag

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index da95b1e52425dbf4e36b3217afb7b592362ebbb0..cbaed084be060631e2b32845a829aaac2f742c96 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -196,14 +196,14 @@ DEFINE_IMPLICATION(es_staging, harmony)
 
 // Features that are complete (but still behind --harmony/es-staging flag).
 #define HARMONY_STAGED(V)                                               \
-  V(harmony_tostring, "harmony toString")                               \
   V(harmony_unicode, "harmony unicode escapes")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                                \
   V(harmony_classes, "harmony classes (implies object literal extension)") \
   V(harmony_computed_property_names, "harmony computed property names")    \
-  V(harmony_object_literals, "harmony object literal extensions")
+  V(harmony_object_literals, "harmony object literal extensions")          \
+  V(harmony_tostring, "harmony toString")
 
 // Once a shipping feature has proved stable in the wild, it will be dropped
 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,