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

    temp.add(context.endOfLeftSegments);
    const bodySegments = temp.makeNext(-1, -1);

    // Make a path: `right` -> `left`.
    makeLooped(this, forkContext.head, context.leftSegments);

    // Update state.
    context.brokenForkContext.add(forkContext.head);
    forkContext.replaceHead(bodySegments);
  }
Makes a code path segment for the body part of a ForInStatement and a
ForOfStatement.
@returns {void}