expand a merge_tests.py 43 to cover reopened issue #2821.
expand a merge_tests.py 43 to cover reopened issue #2821.

* subversion/tests/cmdline/merge_tests.py
  (avoid_repeated_merge_on_subtree_with_merge_info):  expand to cover problem
  with subtree merges described here:
  http://subversion.tigris.org/issues/show_bug.cgi?id=2821#desc22.
  (test_list): Mark avoid_repeated_merge_on_subtree_with_merge_info as XFail.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@870522 13f79535-47bb-0310-9956-ffa450edef68

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