GitLab

Use vpython for `generate_gradle.py` and `list_java_targets.py`

Change-Id: I39bb601add8cc1c019a3aab9bca60bee0e341084
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2315400
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791917}