o Minor bugfixes (logging, testing):
    - Make all of tor's assertion macros support the ALL_BUGS_ARE_FATAL and
      DISABLE_ASSERTS_IN_UNIT_TESTS debugging modes. Implements these modes
      for IF_BUG_ONCE(). (It used to log a non-fatal warning, regardless of
      the debugging mode.) Fixes bug 33917; bugfix on 0.2.9.1-alpha.