popBreakContext() {
    const context = this.breakContext;
    const forkContext = this.forkContext;

    this.breakContext = context.upper;

    // Process this context here for other than switches and loops.
    if (!context.breakable) {
      const brokenForkContext = context.brokenForkContext;

      if (!brokenForkContext.empty) {
        brokenForkContext.add(forkContext.head);
        forkContext.replaceHead(brokenForkContext.makeNext(0, -1));
      }
    }

    return context;
  }
Removes the top item of the break context stack.
@returns {Object} The removed context.