rclcpp multithreaded executor tests are failing

[hidmic]

See here and here. It looks like a regression from ros2/rclcpp#383 which seems odd to me. And of course I can't reproduce locally.

CC @wjwwood, in case he remembers.

[wjwwood]

Maybe it is a regression, @mjcarroll pushed that one across the line. I don't remember the details at this point.

[mjcarroll]

It is, at the very least, far too timing sensitive. I'm going to see if I can rework the test to make it less reliant on time.

[clalancette]

We aren't using this repository anymore for buildfarm issues, so I'm going to archive it. Thus I'm closing out this issue. If you continue to have problems, please report another bug against https://github.com/ros2/ros2. Thank you.