patch 8.2.3737: test fails without the 'autochdir' option

Problem:    Test fails without the 'autochdir' option.
Solution:   Check that the option is available. (Dominique Pellé, closes #9272)
diff --git a/src/testdir/test_cd.vim b/src/testdir/test_cd.vim
index 81ed491..566e9f6 100644
--- a/src/testdir/test_cd.vim
+++ b/src/testdir/test_cd.vim
@@ -226,6 +226,8 @@
 endfunc
 
 func Test_getcwd_actual_dir()
+  CheckOption autochdir
+
   let startdir = getcwd()
   call mkdir('Xactual')
   call test_autochdir()