Fix cycling after addition of the new case simplification.

nset.pas, tcasenode.simplify: don't assume a specific order of the case labels

+ added test based on ppu.pas, tppu.getaint where no matching case label was found because of the ordering


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26825 3ad0048d-3df7-0310-abae-a5850022a9f2