Provide a FS-level test case for rep-sharing that requires content comparison. 
Provide a FS-level test case for rep-sharing that requires content comparison. 

* subversion/tests/libsvn_fs/fs-test.c
  (flag_fs_warnings): New callback.
  (test_rep_sharing_strict_content_check): New test case.
  (test_funcs): Register new test case as XFAIL.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1785734 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion