patch 8.0.0555: toupper/tolower test fails on OSX without Darwin

Problem:    Toupper/tolower test fails on OSX without Darwin.
Solution:   Skip that part of the test also for OSX. (Kazunobu Kuriyama)

src/testdir/test_normal.vim

@@ -1605,7 +1605,7 @@ fun! Test_normal30_changecase()
 
   " Turkish ASCII turns to multi-byte.  On Mac the Turkish locale is available
   " but toupper()/tolower() don't do the right thing.
-  if !has('mac')
+  if !has('mac') && !has('osx')
     try
       lang tr_TR.UTF-8
       set casemap=

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    555,
 /**/
     554,
 /**/