makeForInOfRight() {
    const context = this.loopContext;
    const forkContext = this.forkContext;
    const temp = ForkContext.newEmpty(forkContext);

    temp.add(context.prevSegments);
    const rightSegments = temp.makeNext(-1, -1);

    // Update state.
    context.endOfLeftSegments = forkContext.head;
    forkContext.replaceHead(rightSegments);
  }
Makes a code path segment for the right part of a ForInStatement and a
ForOfStatement.
@returns {void}