Don't allow "static" for class operators or normal methods (except in objects).

pdecsub.pas, pd_static:
  * check whether the given pd is an operator or a class method not inside an Object and generate an error if either of these is true
msg/errore.msg, msgidx.inc, msgtxt.inc:
  * add a message to inform that a certain procedure directive is not allowed

+ added tests

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@23944 3ad0048d-3df7-0310-abae-a5850022a9f2