patch 8.2.0416: test leaves file behind

Problem:    Test leaves file behind.
Solution:   Delete the file.
diff --git a/src/testdir/test_indent.vim b/src/testdir/test_indent.vim
index 42743a6..5e90c87 100644
--- a/src/testdir/test_indent.vim
+++ b/src/testdir/test_indent.vim
@@ -134,10 +134,12 @@
   call assert_equal('GetIndent()', &indentexpr)
   exe "normal Oa\nb\n"
   call assert_equal(['  a', '    b'], getline(1, 2))
+
   set modelineexpr&
   delfunc GetIndent
   let &modeline = modeline
   close!
+  call delete('Xfile.txt')
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab