Merge "Fixed CTS wallpaper tests so they check if the service is available." into pie-cts-dev am: 1d99a0a903 am: f872693f93 am: 9b32322659 am: 0252aba111 am: 3552ff4992

Change-Id: I552e58423d1f94aeff568b95be2cdd447f95dae5