Add an XFail regression test for issue #4444,
"diffing move inside a copy asserts".

* subversion/tests/cmdline/diff_tests.py
  (diff_move_inside_copy, test_list): New test.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1538516 13f79535-47bb-0310-9956-ffa450edef68