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

src/ic/ic.cc

Index: src/ic/ic.cc
diff --git a/src/ic/ic.cc b/src/ic/ic.cc
index e83a4b217d4f0b53c1aa8f9f081f1e68a9570291..810a149936fc6226df794e8f2f3f42b7e0880be0 100644
--- a/src/ic/ic.cc
+++ b/src/ic/ic.cc
@@ -670,6 +670,10 @@ MaybeHandle<Object> LoadIC::Load(Handle<Object> object, Handle<Name> name) {
 
     GlobalContextTable::LookupResult lookup_result;
     if (GlobalContextTable::Lookup(global_contexts, str_name, &lookup_result)) {
+      if (use_ic && LoadGlobalContextFieldStub::Accepted(&lookup_result)) {
+        LoadGlobalContextFieldStub stub(isolate(), &lookup_result);
+        PatchCache(name, stub.GetCode());
+      }
       return FixedArray::get(GlobalContextTable::GetContext(
                                  global_contexts, lookup_result.context_index),
                              lookup_result.slot_index);