Bugs that are older than the switch of v8_foozzie.py to Python3
bisect to the switch commit unfortunately. This change attempts to
let bisect run longer if a python2 executable still exists.

No-Try: true
Bug: chromium:1355824
Change-Id: I457a50af21704ddd2985793861eee8be5601a673
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3856574Reviewed-by: Liviu Rau <liviurau@google.com>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82728}