Move some Android devices to a new host

Hopefully this will help with stability/disconnects.

BUG=skia:3060
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/686153002
Consolidate metrics for ingestion into Ingester.

At the same time add a metric for time since last successful update.

BUG=skia:
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/691603002