Updated:
    builds/zos/runtests: Extract tests to run from tests/Makefile.am
      at runtime, rather than hard coding tests list (to simplfy
      later maintenance).  test_*_tipc is excluded as BUILD_TIPC is
      not defined on z/OS UNIX System Services.  XFAIL_TESTS are also
      excluded, following current logic in tests/Makefile.am