Change the parent reference inside the VMT to an indirect one.

compiler/ncgvmt.pas, TVMTWriter:
  * writevmt: write a reference to the indirect VMT symbol instead of the direct one

rtl/inc/systemh.inc:
  + enable advanced records for system unit
rtl/inc/objpash.inc & rtl/inc/objpas.inc, TVmt:
  * rename vParent to vParentRef and change type to PPVmt for 2.7.1 and newer
  + add new property vParent of type PVmt and which dereferences vParentRef depending on the type
rtl/inc/generic.inc:
  * tobjectvmt: change parent to ppointer for 2.7.1 and newer
  * fpc_check_object_ext: correctly dereference tobjectvmt.parent for 2.7.1 and newer

tests/webtbs/tw16034.pp:
  * adjusted test which directly uses the binary data

git-svn-id: http://svn.freepascal.org/svn/fpc/branches/svenbarth@28341 3ad0048d-3df7-0310-abae-a5850022a9f2