`monocoque test` used to only drive locally-initialized devices directly,
so external tools that read SIMAPI.DAT the same way a real running sim
populates it (dashboards, telemetry viewers) saw nothing during a test
run. Opens the shared memory segment at the start of tester() and mirrors
each simdata update into it via a new update_devices() helper, which also
replaces the ~20 duplicated inline device-update loops throughout tester()
with a single call site.
On exit the segment is reset to an inactive frame (simon=false,
SIMAPI_STATUS_OFF) rather than left at whatever the last active-play frame
was - otherwise external readers see the test run as a sim that's still
actively driving forever, since nothing writes to SIMAPI.DAT again until
the next test/play run.
David Scott