Serializer: assert that we deserialize only one native context.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 2246f6e1a797741fcc40f43d2ff0ee2e993aa1dd..2e46530d95f8010215e15bc7a6a63daf29624591 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -895,6 +895,8 @@ void Genesis::HookUpGlobalObject(Handle<GlobalObject> global_object,
   // Replace outdated global objects in deserialized contexts.
   for (int i = 0; i < outdated_contexts->length(); ++i) {
     Context* context = Context::cast(outdated_contexts->get(i));
+    // Assert that there is only one native context.
+    DCHECK(!context->IsNativeContext() || context == *native_context());
     DCHECK_EQ(context->global_object(), *global_object_from_snapshot);
     context->set_global_object(*global_object);
   }