test: optimize test cases for visual regression test

[pissang]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Optimize test cases from #15599 for visual regression testing tool. To ensure:

1. It needs to reflect the objectives of the test on the screenshot. For example, the animation duration needs to be long so the screenshot will be the intermediate state instead of the final state. The final state can't reflect the animation process.
2. Every test case needs to been added at the bottom. To avoid the changed layout make recorded interactions fail.
3. Every test case should have a title to describe the feature to test.

[echarts-bot]

Thanks for your contribution!
The community will review it ASAP. In the meanwhile, please checkout the coding standard and Wiki about How to make a pull request.

The pull request is marked to be PR: author is committer because you are a committer of this project.

[echarts-bot]

Congratulations! Your PR has been merged. Thanks for your contribution! 👍