Testconfig: Dedicated Ubuntu node to run Android tests

We need to authenticate all Android devices from CI node to be able
to connect those. While there is only three nightly builds currently
running those tests, we can use just one node and clone and authenticate
more later.

Change-Id: Iaf865679f9242766329d0bbf6648ec01db6cde23
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>