python3: Many Py3-compatibility roller fixes

Bug: 465
Change-Id: I1b0e601a93982999fec14b4f6a458e2570e770fc
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/59488
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Oliver Newman <olivernewman@google.com>
30 files changed