Removed vecn nodes from constant pointer address calculations to absolute variables, since only subscripts were being handled leading to problems like those described in issue 17118.
After the removal of vecn these values seem to be handled easily by subsequent optimizations anyway.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28978 3ad0048d-3df7-0310-abae-a5850022a9f2