bevy_ecs system stepping tests are failing and are not tested in CI

## Bevy version

#17651

## What you did

cargo test --package bevy_ecs --lib --all-features

## What went wrong

```
failures:
schedule::stepping::tests::clear_breakpoint
schedule::stepping::tests::clear_schedule
schedule::stepping::tests::clear_schedule_then_set_behavior
schedule::stepping::tests::clear_system
schedule::stepping::tests::continue_always_run
schedule::stepping::tests::continue_breakpoint
schedule::stepping::tests::continue_never_run
schedule::stepping::tests::continue_step_continue_with_breakpoint
schedule::stepping::tests::disabled_always_run
schedule::stepping::tests::disabled_breakpoint
schedule::stepping::tests::disabled_never_run
schedule::stepping::tests::multiple_calls_per_frame_continue
schedule::stepping::tests::multiple_calls_per_frame_step
schedule::stepping::tests::remove_schedule
schedule::stepping::tests::set_behavior_then_clear_schedule
schedule::stepping::tests::step_always_run
schedule::stepping::tests::step_breakpoint
schedule::stepping::tests::step_never_run

test result: FAILED. 643 passed; 18 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.04s
```

## Additional information

These don't seem to be tested in CI somehow? Bisecting the start of the failure would be nice.

We should fix these tests, and ensure that our build system is exercising these tests. @mockersf or @BD103 may have ideas on the latter.