[stubs]: Support 1->2 byte copies in CopyStringCharacters

src/zone/zone.h

Index: src/zone/zone.h
diff --git a/src/zone/zone.h b/src/zone/zone.h
index 892dfb7f5662a8b551a737535725435a2b39a4f8..4e3b96eb206e8ff1a247130600ea3ac5e341e3c8 100644
--- a/src/zone/zone.h
+++ b/src/zone/zone.h
@@ -160,6 +160,13 @@ class ZoneList final : public List<T, ZoneAllocationPolicy> {
   ZoneList(int capacity, Zone* zone)
       : List<T, ZoneAllocationPolicy>(capacity, ZoneAllocationPolicy(zone)) {}
 
+  // Construct a new ZoneList from a std::initializer_list
+  ZoneList(std::initializer_list<T> list, Zone* zone)
+      : List<T, ZoneAllocationPolicy>(static_cast<int>(list.size()),
+                                      ZoneAllocationPolicy(zone)) {
+    for (auto& i : list) Add(i, zone);
+  }
+
   void* operator new(size_t size, Zone* zone) { return zone->New(size); }
 
   // Construct a new ZoneList by copying the elements of the given ZoneList.