Fix bug in tool-info module for CPAchecker that could lead to duplicate command-line options.
Fix bug in tool-info module for CPAchecker
that could lead to duplicate command-line options.

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