patch 8.2.2570: tests fail when run as root

Problem:    Tests fail when run as root.
Solution:   Add a comment mentioning the expected failure. (issue #7919)

src/testdir/test_edit.vim

@@ -1704,6 +1704,7 @@ func Test_edit_charconvert()
 endfunc
 
 " Test for editing a file without read permission
+" NOTE: if you run tests as root this will fail.  Don't run tests as root!
 func Test_edit_file_no_read_perm()
   CheckUnix
   call writefile(['one', 'two'], 'Xfile')

src/testdir/test_excmd.vim

@@ -333,6 +333,7 @@ func Test_winsize_cmd()
 endfunc
 
 " Test for the :redir command
+" NOTE: if you run tests as root this will fail.  Don't run tests as root!
 func Test_redir_cmd()
   call assert_fails('redir @@', 'E475:')
   call assert_fails('redir abc', 'E475:')

src/testdir/test_help.vim

@@ -74,6 +74,7 @@ func Test_help_completion()
 endfunc
 
 " Test for the :helptags command
+" NOTE: if you run tests as root this will fail.  Don't run tests as root!
 func Test_helptag_cmd()
   call mkdir('Xdir/a/doc', 'p')
 

src/testdir/test_writefile.vim

@@ -406,6 +406,7 @@ func Test_patchmode()
 endfunc
 
 " Test for writing to a file in a readonly directory
+" NOTE: if you run tests as root this will fail.  Don't run tests as root!
 func Test_write_readonly_dir()
   " On MS-Windows, modifying files in a read-only directory is allowed.
   CheckUnix

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2570,
 /**/
     2569,
 /**/