dillon1000/react

Combine commitWork into single switch statement

commitWork is forked into a separate implementation for mutation mode
(DOM) and persistent mode (React Native). But unlike when it was first
introduced, there's more overlap than differences between the forks,
mainly because we've added new types of fibers. So this joins the two
forks and adds more local branches where the behavior actually
diverges: host nodes, host containers, and portals.