Even better
Don't explode if the pid vanishes during is_gm_process/2. Keep on handling instrumented msgs while we are waiting for things to shut down, so that... they can.
Don't expect message delivery until we have had the joined callback invoked.
Oops, 3d7b7d85df74 got us into a degenerate case where our tests only ever consisted of joins.
Wait until a GM has actually left before forgetting it.
Be more correct about dynamic vs symbolic state; this gets us back into a position where we are actually testing sending messages :-/
Various bug fixes in generating command sequences.
Add instrumenting for monitors and Mnesia transactions. It actually all seems to work now.
Merge bug24929.