When allocating slots for eager scheduling, it can happen that allocated slots get failed after they are assigned to the Execution (e.g. due to a TaskExecutor heartbeat timeout). If there are still some uncompleted slot futures, then this will not be noticed since the Execution is assigned to the LogicalSlot only after all slot futures are completed. Therefore, the allocated slot failure will go unnoticed until this happens.
In order to speed up failures, we should directly assign the Execution to the LogicalSlot once the slot is assigned to the Execution.