avoid Eager macro-expansion failure: (void-function string-to-list)

* loadup.el [ns]: "ucs-normalize" uses `string-to-list' which is defined
  in "mule-util", so we have to load "mule-util" before "ucs-normalize",
  otherwise I get "Eager macro-expansion failure" on "make bootstrap"

lisp/loadup.el

@@ -301,6 +301,7 @@
       ;; already produced, because it needs uni-*.el files that might
       ;; not be built early enough during bootstrap.
       (when (load-history-filename-element "charprop\\.el")
+        (load "international/mule-util")
         (load "international/ucs-normalize")
         (load "term/ns-win"))))
 (if (fboundp 'x-create-frame)