[WIP] Test(Scheduler): More tests and disabled sponsoring

[Fahrrader]

[Fahrrader]

Two tests on canceling scheduling fail: Can schedule a scheduled operation of canceling the scheduled operation and Can't cancel a non-owned scheduled operation

[kozyrevdev]

@mrshiposha забери к себе и закрой ветку/пр

[mrshiposha]

@kozyrevdev все новые тесты на scheduler были основаны на этом PR. Он уже не актуален, закрываю.