Add cqe overflow assert

[1Jo1]

Motivation:

we need to ensure that the number of lost completion events is always zero to avoid inconsistency

Modifications:

Add a cqe overflow assert

Result:

regarding future core changes, we know when cqe events are lost

[1Jo1]

tbh it doesnt make sense to add assert to the cqe queue, I think we should move that that to sqe queue

[1Jo1]

it seems we don't track the number of events in io_uring that are not finished, I thought we had something like that, I guess it's probably safer to add that :)

[1Jo1]

another idea would be, just increase the cqe ring size like 3x of sqe size, default is 2x of the sqe size