Boeing confirmed to me that they are resuming standard Boeing production flight testing under the approval of the FAA. The production flights will be normal Boeing flights meant to validate the aircraft's systems. There are no restrictions that the FAA has placed on these aircraft. All airplanes that are to be production tested will have the new batteries and the containment system installed. ZA512 (LN 83, JA818A) for ANA was the first aircraft to fly today and fly with the new battery and containment system on a functional check flight.
We should see more and more 787s parked in Everett and Charleston to start conducting their standard B-1, B-2 and C-1, C-2 flights but these airplanes won't be delivered until the FAA has certified the batteries and the containment system for commercial use.