Issue a warning if the system swapped during benchmarking (see #2).
Issue a warning if the system swapped during benchmarking
(see #2).

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