harmony-scoping: Implement LoadIC handler for loads from global contexts.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 9101576b7b91a3b4c9746e1ca11da7bb3eb51320..24d0ac14c8c01a4981ab6d452dbdbffeff7b7453 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -6276,6 +6276,8 @@ class HObjectAccess FINAL {
 
   static HObjectAccess ForContextSlot(int index);
 
+  static HObjectAccess ForGlobalContext(int index);
+
   // Create an access to the backing store of an object.
   static HObjectAccess ForBackingStoreOffset(int offset,
       Representation representation = Representation::Tagged());