Eng 6012 inexists sp

I don't think pulling the hasMatchingTuple declaration/initialization out of the loop buys you anything because its value must be re-evaluated on every iteration for each tuple - 
if (predicate == NULL || hasMatchingTuple == true) {
    // Insert tuple to the output table
}
so after the loop, the hasMatchingTuple could be FALSE but the output table not empty. Also, the offset must be taken into the consideration, right? The tuple may pass the predicate but won't be inserted into the output table because of the offset.
Completely agree that hasNullTuple check is sufficient.
I am making changes in my branch https://github.com/alexeevm/voltdb/blob/ENG-6012-inexists-sp