checker: Reduce memory usage
checker: Reduce memory usage

    benchmark              old bytes     new bytes     delta
    BenchmarkChecker-4     25551348      4288037       -83.22%

byo/restic,restic/restic,jayme-github/restic,middelink/restic,byo/restic,ar-jan/restic,kurin/restic,ar-jan/restic,kurin/restic,middelink/restic,fawick/restic,stuertz/restic,jayme-github/restic,fawick/restic,stuertz/restic,restic/restic