[infra] Make jobs use Gold's public hashes

Change-Id: Ia5da00913d0b96e9edc47f8b2274bd26c35c251c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/469457
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
5 files changed