New unit test for svn_path_get_longest_ancestor.
New unit test for svn_path_get_longest_ancestor.

* subversion/tests/libsvn_subr/path-test.c
  (test_get_longest_ancestor): New function
  (test_funcs): add the new unit test.

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