resumed->rescheduled is an invalid transition

[hendrikmakait]

def test_resumed_executing_task_releases_resources_on_reschedule(ws_with_running_task):
    ws = ws_with_running_task

    ws.handle_stimulus(FreeKeysEvent("cancel", ["x"]))
    assert ws.tasks["x"].state == "cancelled"
    assert ws.available_resources == {"R": 0}

    instructions = ws.handle_stimulus(
        ComputeTaskEvent.dummy(
            key="y",
            who_has={"x": ["127.0.0.1:1235"]},
            nbytes={"x": 8},
            stimulus_id="compute",
        )
    )
    assert ws.tasks["x"].state == "resumed"
    assert not instructions

    ws.handle_stimulus(
        RescheduleEvent(key="x", stimulus_id="reschedule")
    )
    assert ws.tasks["x"].state == "rescheduled"
    assert ws.available_resources == {"R": 1}

fails with distributed.worker_state_machine.InvalidTransition: InvalidTransition: x :: resumed->rescheduled. However, this might be a legitimate series of events to my understanding.

[crusaderky]

1. task x is started on w1
2. task x is cancelled
3. task x is started on w2 and terminates successfully
4. task y, which depends on x, is started on w1 -> task x is transitioned to resumed(fetch)
5. task x calls raise Reschedule()

There's no such thing as a ("resumed" "rescheduled") transition.
The worker will kill itself off with @fail_hard, losing all data stored on itself.

This is tightly related to #6709.