patch 8.2.5083: autocmd test still fails on MS-Windows

Problem:    Autocmd test still fails on MS-Windows.
Solution:   Change backward to forward slashes.
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index d0b5b5a..e9a59c2 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -2108,15 +2108,12 @@
   exe 'lcd ' .. fnameescape(s:dir_bar)
   call assert_equal(expected, s:li)
 
-  let save_shellslash = &shellslash
-  set shellslash
   exe 'cd ' .. s:dir_foo
   exe 'cd ' .. s:dir_bar
   autocmd! test_dirchanged DirChanged global let g:result = expand("<afile>")
   cd -
-  call assert_equal(s:dir_foo, g:result)
+  call assert_equal(s:dir_foo, substitute(g:result, '\\', '/', 'g'))
 
-  let &shellslash = save_shellslash
   call s:After_test_dirchanged()
 endfunc