mpseventtxt must not itself output telemetry, otherwise it is likely to overwrite the telemetry it is converting.
Park the arena before calling mps_chain_destroy.
Speed up mpsicv by reducing number of objects and by only running the test once (there's no inlined mps_tramp any more).
Improve coverage of events by turning on MPS_TELEMETRY_CONTROL=all and by running mpseventcnv, mpseventtxt and (if available) mpseventsql.