clean up stemmer gpu, check correctness
clean up stemmer gpu, check correctness

hoehnp/sirius,claritylab/sirius,hoehnp/sirius,hoehnp/sirius,claritylab/sirius,hoehnp/sirius,claritylab/sirius,claritylab/sirius,claritylab/sirius,hoehnp/sirius,hoehnp/sirius,claritylab/sirius,claritylab/sirius,hoehnp/sirius