Relaunching failed bisects requires too many scrolls, clicks and weird string remembering. Ideally a failed bisect would include a link to relaunch in the output it posts to the perf bug.

Something like:

Bisect job status: failed

If the underlying cause for this failure has been addressed, you can retry this bisect job by clicking here: https://chromeperf.appspot.com/relaunch_bisect/1231234455

<rest of the failed bisect output>