libBacktraceRecording __introspection_dispatch_queue_get_pending_items is
changing the data it returns; this change accepts either the old format or
the new format.  It doesn't yet benefit from the new format's additions -
but I need to get this checked in so we aren't rev-locked.
Also add a missing .i entry for SBQueue::GetNumRunningItems() missing from
the last checkin.
<rdar://problem/16272115>