Hmm... One way that I look at it is evolutionary computation is an optimization strategy. It's characterized by tracking a population of candidates, discarding the lowest scoring, mutating the survivors, and cross-combining elements from multiple candidates.

RL is an optimization domain. It's the name of the problem, not the solution. You can straightforwardly use evolutionary algorithms on RL problems. However, a lot of the recent success in RL has come from using deep learning to try to solve various RL problems, not from trying evolutionary computation.