Revision 1852436

Make 'svn update' not record a tree conflict when deleting an unmodified
directory which happens to contain unversioned items. Instead, just leave
the unversioned items behind on disk when deleting the unmodified directory,
which matches the behaviour of Subversion 1.8.

Prompted by a question on users@:
https://svn.haxx.se/users/archive-2019-01/0060.shtml

* subversion/libsvn_wc/update_editor.c
  (check_tree_conflict): Ignore unversioned items during check for local mods.
   This prevents a tree conflict from being recorded.

* subversion/tests/cmdline/switch_tests.py
  (tolerate_local_mods): Don't expect an unversioned item to cause a tree
   conflict. Add the item to version control instead to meet this test's
   expectations.

* subversion/tests/cmdline/update_tests.py
  (update_keeps_unversioned_items_in_deleted_dir, test_list): New test
   which ensures that update will leave unversioned items on disk when
   deleting an unmodified directory.