fix refresh on El Capitan

When restoring autodisplay, need to check whether a display was
lost since display was suspended.

(cherry picked from commit 9bf18505d5)

gui-lib/mred/private/wx/cocoa/frame.rkt

@@ -429,7 +429,8 @@
       (when (zero? flush-disabled)
         (tellv cocoa enableFlushWindow)
         (when (version-10.11-or-later?)
-          (tellv cocoa setAutodisplay: #:type _BOOL #t))))
+          (tellv cocoa setAutodisplay: #:type _BOOL #t)
+          (tellv cocoa displayIfNeeded))))
 
     (define/public (force-window-focus)
       (let ([next (get-app-front-window)])