Refactor dynamic SlotID

In FLINK-14189, we specified that the SlotID whose slot number is -1 represents the dynamic slot. However, the SlotID with a negative slot number will be treated as invalid in other components, e.g. SlotPool and SlotManager. We have to remove a lot of sanity checks with this change, which is error-prone. The evidence is that there are still some sanity checks that have not been removed, e.g. sanity checks in AllocatedSlotInfo.
We propose to assign an increasing number larger than the numberOfSlot to dynamic slots. In this way, we can decouple the JM and RM with the dynamic slot logic.