Use SkiaGoldClient to compare golden images in DevTools integration tests

At some point, we could move away from a poor man solution of comparing image bytes to using Skia Gold.

file here: https://github.com/flutter/flutter/blob/master/packages/flutter_goldens_client/lib/skia_client.dart

首先阅读 packages/flutter_goldens_client/lib/skia_client.dart，然后找到比较图像字节的 DevTools 集成测试。确认这些测试目前如何执行 golden 比较；完成的标准是它们使用 SkiaGoldClient，而不是现有的字节比较方式。

由索引模型根据 Issue 内容生成。