External Materialization, When TTL is less than loading time, the scheduling is off

During managed external mateiralization,

1) if the TTL specified is less than the amount of load time
2) Then, if other nodes check the status at "LOADING", and the elapsed time is calculated from the time on the Status table. Which when goes over the TTL, it will be a negative value
3) Then, the scheduling algorithm schedules the next check immediately, which will be exactly same as one before as it also checks from the last updated time. Thus going into a tight loop which consume all the resources spinning.

Correct this to check that, the scheduler always schedules next check atleast a default time after the previous one, which is currently at a minute.