Request: Multiple results per commit for track style benchmarks

[andrewchambers]

It seems with track_ style benchmarks its not possible to rerun a benchmark and show multiple results for a given git commit. Each time I try to do so it overwrites the old result, even if I add --append-samples it still overrides tack benchmarks.

[HaoZeke]

Could you add a MWE? Also were the previous samples run with --record-samples first?