does-hunspell-works-under-valgrind: workaround the testcase
    
    echo "NEWSX" | hunspell -a with and w/o valgrind differed in
    lower case. This could be workarounded by running such a command
    under --tool=none.
    
    Jan Kratochvil suggested the better workaround finding out
    spelling suggestions somehow were based on the processor time used by
    the process. And so overriding clock to simply always return zero means
    the process cannot observe the cpu time used.