Revert "[python3] More Recipes -> Python 3 fixes"

This reverts commit 12e786730f7d6b7b31bdf2fdf22e51dea8d37717.

Reason for revert: missing CIPD package on armv6l

Original change's description:
> [python3] More Recipes -> Python 3 fixes
>
> - Set environment variables to force usage of Python 3 in more places
> - Fix more compatibility issues
> - Mark recipes as only supporting Python 3
> - Includes a roll of the infra code
>
> Change-Id: I24e3827a6402c454bdc9467d28864d360632f9e6
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/470303
> Reviewed-by: Ravi Mistry <rmistry@google.com>
> Commit-Queue: Eric Boren <borenet@google.com>

Change-Id: If7b6fcb7838ac053af2c5eb45a7a1ac4aed340a5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/472736
Auto-Submit: Eric Boren <borenet@google.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
112 files changed