Add a testbed project for watchOS

### What is the problem or limitation you are having?

There's not currently any way to (easily) test the operation of watchOS.

### Describe the solution you'd like

The Python patch should be extended to include a testbed project for watchOS.

### Describe alternatives you've considered

None

### Additional context

watchOS projects are quite different to other platforms; however, it may be possible to crib a lot of content from the iOS testbed project.

It may also be worth investigating if a single testbed can be used for all Apple platforms, with multiple targets in a single project.

首先定位 Python 补丁和现有的 iOS 测试平台项目，然后比较其项目和 targets 的结构。调查 watchOS 是否需要单独的测试平台，还是可以共享一个多 target 的 Apple 项目；完成的标准是 repository 包含一个可运行的 watchOS 测试平台，并且项目方案已经确定。

由索引模型根据 Issue 内容生成。