Fix initialization/finalization of good old objects that have a parent

ncgrtti.pas, TRTTIWriter:
  * fields_write_rtti_data: also write the "weak" entry for the the parent "field" of an object


git-svn-id: http://svn.freepascal.org/svn/fpc/branches/svenbarth@28914 3ad0048d-3df7-0310-abae-a5850022a9f2