vulcanizer: Use sys.executable to find python
vulcanizer: Use sys.executable to find python

Bug: chromium:1205617
Change-Id: I81e83924755c275102df3ec064e58856c6dd0423
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/2929041
Reviewed-by: John Chen <334fbfbb4df7c78f091ea1b77c69ca6ac731a3f3@chromium.org>
Reviewed-by: Sébastien Marchand <b98658856fe44d267ccfa37efbb15fc831b08ae9@chromium.org>
Commit-Queue: Deep Roy <196de8ecef43ff77ba1a773ccd52374e3849c302@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult