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)
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index 155ddbf..21d6aa9 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -1605,7 +1605,7 @@
 
   " 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=
diff --git a/src/version.c b/src/version.c
index 578cfe3..7cf7644 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    555,
+/**/
     554,
 /**/
     553,