patch 8.2.5104: test hangs on MS-Windows

Problem:    Test hangs on MS-Windows.
Solution:   Skip another test on MS-Windows.

src/testdir/test_retab.vim

@@ -1,5 +1,7 @@
 " Test :retab
 
+source check.vim
+
 func SetUp()
   new
   call setline(1, "\ta  \t    b        c    ")
@@ -90,6 +92,9 @@ func RetabLoop()
 endfunc
 
 func Test_retab_endless()
+  " FIXME: why does this hang on MS-Windows?
+  CheckNotMSWindows
+
   " inside try/catch we catch the error message
   new
   call setline(1, "\t0\t")
@@ -105,7 +110,7 @@ func Test_retab_endless()
 endfunc
 
 func Test_nocatch_retab_endless()
-  " FIXME: why does this hang on MS-Windows?
+  " FIXME: does this hang on MS-Windows?
   CheckNotMSWindows
 
   " not inside try/catch an interrupt is generated to get out of loops

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    5104,
 /**/
     5103,
 /**/