Remove check for appdefined events on the queue (bug#65843)

It seems this was likely a bug in macOS 10.10.1. I have no way to find
out when it was fixed, but hopefully before 10.10.5, the most recent
release of that version.

* src/nsterm.m (ns_send_appdefined): Remove check for whether previous
appdefined events have been lost.

src/nsterm.m

@@ -4560,21 +4560,6 @@ Function modeled after x_draw_glyph_string_box ().
   /* Only post this event if we haven't already posted one.  This will end
      the [NXApp run] main loop after having processed all events queued at
      this moment.  */
-
-#ifdef NS_IMPL_COCOA
-  if (! send_appdefined)
-    {
-      /* OS X 10.10.1 swallows the AppDefined event we are sending ourselves
-         in certain situations (rapid incoming events).
-         So check if we have one, if not add one.  */
-      NSEvent *appev = [NSApp nextEventMatchingMask:NSEventMaskApplicationDefined
-                                          untilDate:[NSDate distantPast]
-                                             inMode:NSDefaultRunLoopMode
-                                            dequeue:NO];
-      if (! appev) send_appdefined = YES;
-    }
-#endif
-
   if (send_appdefined)
     {
       NSEvent *nxev;