Add a non-regression diff test against bug that r26503 fixes.  (see http://subversion.tigris.org/servlets/ReadMsg?listName=dev&msgNo=129865)
Add a non-regression diff test against bug that r26503 fixes.  (see
http://subversion.tigris.org/servlets/ReadMsg?listName=dev&msgNo=129865)

* subversion/tests/cmdline/diff_tests.py
  (diff_backward_repos_wc_copy): new test for backward repos->wc diff
  against copied-file.
  (test_list): add this new test.

Approved by: kfogel


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@867398 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion