On the fsx branch: add an initial test for the svn_packed__* API.

* build.conf
  (packed-data-test): new target
  (__ALL_TESTS__): register new target

* subversion/tests/libsvn_subr
  (svn:ignore): ignore new test binary

* subversion/tests/libsvn_subr/packed-data-test.c
  (): new test


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsx@1508526 13f79535-47bb-0310-9956-ffa450edef68