Specify the version for Robolectric version

The previous default version was 3.1.1, so specifying all existing
projects to that. Please migrate to new version (3.4.2 as of today)
at your convenience.

See robolectric.org/migrating for instructions on migrating.

Test: m RunFrameworksServicesRoboTests RunCarMessengerRoboTests \
        RunStorageManagerRoboTests RunCarSettingsRoboTests \
        RunEmergencyInfoRoboTests RunManagedProvisioningRoboTests \
        RunTurboRoboTests RunStorageManagerGoogleRoboTests \
        RunBluetoothRoboTests

Change-Id: Ib917f1e560f862bea19ca16ab4c1b99886980937