add z3 as supported tool
add z3 as supported tool

ultimate-pa/benchexec,ultimate-pa/benchexec,dbeyer/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,IljaZakharov/benchexec,IljaZakharov/benchexec,dbeyer/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,dbeyer/benchexec,IljaZakharov/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,IljaZakharov/benchexec