[array] Add default methods again, this time the full set

Should add tests.

src/hb-array.hh

@@ -51,6 +51,11 @@ struct hb_array_t : hb_iter_with_fallback_t<hb_array_t<Type>, Type&>
    * Constructors.
    */
   hb_array_t () = default;
+  hb_array_t (const hb_array_t&) = default;
+  ~hb_array_t () = default;
+  hb_array_t& operator= (const hb_array_t&) = default;
+  hb_array_t& operator= (hb_array_t&&) = default;
+
   hb_array_t (Type *array_, unsigned int length_) : arrayZ (array_), length (length_) {}
   template <unsigned int length_>
   hb_array_t (Type (&array_)[length_]) : hb_array_t (array_, length_) {}
@@ -303,6 +308,11 @@ struct hb_sorted_array_t :
   static constexpr bool is_sorted_iterator = true;
 
   hb_sorted_array_t () = default;
+  hb_sorted_array_t (const hb_sorted_array_t&) = default;
+  ~hb_sorted_array_t () = default;
+  hb_sorted_array_t& operator= (const hb_sorted_array_t&) = default;
+  hb_sorted_array_t& operator= (hb_sorted_array_t&&) = default;
+
   hb_sorted_array_t (Type *array_, unsigned int length_) : hb_array_t<Type> (array_, length_) {}
   template <unsigned int length_>
   hb_sorted_array_t (Type (&array_)[length_]) : hb_array_t<Type> (array_) {}