Upgrading chaos app to python3 runtime

BUG=chromium:1032597

Change-Id: Iaee3f06cfdfc881a75f654dd789bf729e9cd37bc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/2399180
Reviewed-by: Dinesh Kumar Sunkara <dsunkara@google.com>
Reviewed-by: Aashutosh Kalyankar <aashutoshk@chromium.org>
Reviewed-by: Katherine Threlkeld <kathrelkeld@chromium.org>
Tested-by: Aashutosh Kalyankar <aashutoshk@chromium.org>
Auto-Submit: Aashutosh Kalyankar <aashutoshk@chromium.org>
Commit-Queue: Aashutosh Kalyankar <aashutoshk@chromium.org>
4 files changed