dillon1000/react

[Fiber] Fix infinite loop in scheduler and add more tests (#8172)

* Make test more complete

* Add a failing test for scheduling in reverse order

It hangs forever because we don't clear next pointer when unscheduling a root. Therefore, when it's scheduled again, it brings all its previous chain with it, potentially creating a cycle.

* Clear the next pointer when unscheduling a root

Fixes a potential infinite cycle when we reschedule a root.

* Add new tests to Fiber test tracker