Add test case for "symmetric" splitting of pack files.
Add test case for "symmetric" splitting of pack files.

* subversion/tests/libsvn_fs_fs/fs-pack-test.c
  (large_log): former huge_log but with string size as parameter
  (huge_log): implement in terms of large_log
  (get_set_large_revprop_packed_fs): new test
  (test_funcs): register new test

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