Fix for Mantis #26483. This regression was introduced by famous revision 27861 which introduced partial specializations (and thus that specializations can be part of local- and parasymtables as well).

symtable.pas, is_visible_for_object:
  * if the symtable belongs to a specialization we need to ignore any owning local- or parasymtable as well to determine which unit it belongs to

+ added test

git-svn-id: trunk@29482 -