patch 8.2.2623: some tests fail when run as root

Problem:    Some tests fail when run as root.
Solution:   Use CheckNotRoot.
diff --git a/src/testdir/test_edit.vim b/src/testdir/test_edit.vim
index 0b44c7d..dd7e743 100644
--- a/src/testdir/test_edit.vim
+++ b/src/testdir/test_edit.vim
@@ -1704,9 +1704,10 @@
 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
+  CheckNotRoot
+
   call writefile(['one', 'two'], 'Xfile')
   call setfperm('Xfile', '-w-------')
   new