test: add performance optimization verification test

[Srajan-Sanjay-Saxena]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Fixes canvas laggy rendering for geo maps with many labels by optimizing ZRender refresh cycles to prevent unnecessary re-renders.

Fixed issues

• [Bug] geo地图大数据量点位label展示卡顿，canvas卡顿更严重 #21331: Canvas laggy rendering with geo maps containing many labels

Details

Before: What was the problem?

Geo maps with many data points and labels caused performance issues due to excessive refresh cycles in ZRender:

• Multiple refresh() calls restarted animation loop unnecessarily (8 animation starts for 5 refresh calls)
• Fixed 10-frame sleep threshold wasn't optimal for complex scenes
• Redundant hover refresh requests wasted resources
• Demo showing issue: https://www.makeapie.cn/echarts_content/xVNl_-jjok.html

After: How does it behave after the fixing?

Performance optimizations in ZRender prevent unnecessary re-renders:

• ✅ Duplicate refresh prevention: 8 → 1 animation starts
• ✅ Adaptive sleep threshold: Complex scenes sleep sooner (3-5 frames vs 10)
• ✅ Hover refresh optimization: Prevents redundant flag setting
• ✅ Automated test verification: test/test-optimizations.html

Document Info

One of the following should be checked.

• This PR doesn't relate to document changes
• The document should be updated later
• The document changes have been made in apache/echarts-doc#xxx

Misc

Security Checking

• This PR uses security-sensitive Web APIs.

ZRender Changes

• This PR depends on ZRender changes (perf: optimize refresh cycles to prevent unnecessary re-renders ecomfe/zrender#1142).

Related test cases or examples to use the new APIs

• test/test-optimizations.html - Automated verification of all performance optimizations
• Tests duplicate refresh prevention (8 → 1 animation starts)
• Tests adaptive sleep threshold functionality
• Tests hover refresh optimization
• Provides automated verification of zrender performance improvements

Merging options

• Please squash the commits into a single one when merging.

Other information

Performance improvements verified with automated tests showing significant reduction in unnecessary animation restarts and better resource management for complex visualizations.

[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.

This PR depends on ZRender changes. Please update the ZRender dependency to the latest nightly version including this change, which takes place everyday at 8:00 UTC (16:00 Beijing Time).
You can use npm i zrender@npm:zrender-nightly@dev to update package.json.
If you have any question about this, please leave a comment and we will give you extra help on this.

[Srajan-Sanjay-Saxena]

i have upgraded the package of zrender to nightly in commit 5af7efd

[Ovilia]

It doesn't seem to make sense calling zr.refresh(); multiple times. First of all, zrender should be a black-box when using ECharts and developers are not expected to call this function manually.