Extend an export test to expose a bug in the case where a file is locally replaced and we're exporting the base version.
Extend an export test to expose a bug in the case where a file is
locally replaced and we're exporting the base version.

* subversion/tests/cmdline/export_tests.py
  (export_working_copy_at_base_revision): Extend to cover all supported
    combinations of file/dir modify/add/delete/replace.
  (test_list): Mark that test as XFail.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion