patch 8.2.5103: build fails with small features

Problem:    Build fails with small features.
Solution:   Add #ifdef.  Skip test on MS-Windows.

src/testdir/test_retab.vim

@@ -105,6 +105,9 @@ func Test_retab_endless()
 endfunc
 
 func Test_nocatch_retab_endless()
+  " FIXME: why does this hang on MS-Windows?
+  CheckNotMSWindows
+
   " not inside try/catch an interrupt is generated to get out of loops
   new
   call setline(1, "\t0\t")