Our svn:ignore settings prefer FSFS test repositories names to
start with "test-repo-".  So, (pre-)fix the ones that don't.

* subversion/tests/libsvn_fs_fs/fs-fs-fuzzy-test.c
  (fuzzing_set_byte_test,
   fuzzing_invert_byte_test,
   fuzzing_increment_byte_test,
   fuzzing_decrement_byte_test,
   fuzzing_null_byte_test): Prefix the repo name with "test-repo".

* subversion/tests/libsvn_fs_fs/fs-fs-private-test.c
  (create_greek_repo,
   get_repo_stats,
   dump_index): Same - using the REPO_NAME #define.

* subversion/tests/libsvn_fs_fs/fs-fs-pack-test.c
  (get_set_multiple_huge_revprops_packed_fs,
   upgrade_new_txns_to_log_addressing,
   upgrade_old_txns_to_log_addressing,
   metadata_checksumming,
   revprop_caching_on_off): Same.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1633238 13f79535-47bb-0310-9956-ffa450edef68