patch 8.2.2609: test disabled on MS-Windows even though it should work

Problem:    Test disabled on MS-Windows even though it should work.
Solution:   Restore the condition for skipping the test. (Ken Takata,
            closes #7970)

src/testdir/test_startup.vim

@@ -109,7 +109,9 @@ func Test_pack_in_rtp_when_plugins_run()
 endfunc
 
 func Test_help_arg()
-  CheckNotMSWindows
+  if !has('unix') && has('gui_running')
+    throw 'Skipped: does not work with gvim on MS-Windows'
+  endif
 
   if RunVim([], [], '--help >Xtestout')
     let lines = readfile('Xtestout')

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2609,
 /**/
     2608,
 /**/