count_foreach() must not fail calculation if there is no data

Steps to reproduce:

1. Create host and add one item that is not receiving any data (e.g. trapper item1[1])
2. Add calculated item calc1 with formula: count(//item1[1],1h)
3. Observe that calc1 has last value 0
4. Add calculated item calc1.aggregate with formula: sum(count_foreach(//item1[*],1h))

Result:
calc1.aggregate turns Unsupported with the message:

Cannot evaluate function: no data for query at "count_foreach(//item1[*],1h))".

Expected:
Given that count(//item1[1],1h) properly handles the situation when there is no history for the item, I expect the same from count_foreach(). It must return a set of values 0 by the number of items found, not an empty set.