bug fix: walltime measurements were ignored and lost
bug fix: walltime measurements were ignored and lost

sosy-lab/benchexec,IljaZakharov/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,dbeyer/benchexec,IljaZakharov/benchexec,dbeyer/benchexec,bjowac/impara-benchexec,martin-neuhaeusser/benchexec,sosy-lab/benchexec,cheshire/benchexec,michkot/benchexec,IljaZakharov/benchexec,IljaZakharov/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,martin-neuhaeusser/benchexec,michkot/benchexec,ultimate-pa/benchexec,martin-neuhaeusser/benchexec,bjowac/impara-benchexec,cheshire/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,bjowac/impara-benchexec,sosy-lab/benchexec,michkot/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,martin-neuhaeusser/benchexec,cheshire/benchexec