Remove timing checks from tests

[tkoolen]

They're just too flaky.

[ChrisRackauckas]

Would you guys want a dedicated CI to run performance regressions? We're trying to put such a thing together and am interested in what projects want in.

[tkoolen]

For this issue, it's not really about performance; the current timing checks are with trivial problems where I'm just making sure the solve call doesn't return too quickly when I add a RealtimeRateLimiter or when I send a command to pause simulation for a while.

That said, I'm potentially interested in CI benchmarking. Are you talking about something like NanoSoldier?

[ChrisRackauckas]

Yeah, we're trying to get funding to start running a Nanosoldier for packages.