Fix startup problem in Lazarus if compiled with ARC-branch compiler.

rtl/inc/objpash.inc:
  + new constant for the offset to the VMT field for the Reference Count offset
  * correctly calculate the first offset of the virtual methods of the VMT


git-svn-id: http://svn.freepascal.org/svn/fpc/branches/svenbarth@28962 3ad0048d-3df7-0310-abae-a5850022a9f2