Provide a regression test for issue #4577.
Provide a regression test for issue #4577.

* subversion/tests/libsvn_fs_fs/fs-fs-pack-test.c
  (delta_chain_with_plain): New test.
  (test_funcs): Register new test.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1677267 13f79535-47bb-0310-9956-ffa450edef68

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