JetMonitoring: Use vector rather than list for temporary jet list.

It's usually a mistake to use std::list rather than std::vector. In this case, std::list was used because we want to delete elements from the middle. However, since we don't care about the ordering, we can do it faster with a vector by swapping the element to be deleted to the end of the vector and then popping it off.

Also use min_transformed_element from CxxUtils.