Migrate testing infrastructure on 3.x-stable

[timmywil]

Summary

This is the 3.x version of #5418. There are some changes in this PR that I plan on copying to the main branch.

• I've refactored the browserstack workers logic and queue to reuse browser instances. This has reduced the testing time of all 3.x browsers from 35-45min to 5-10min! It uses our built-in report API to set the browser URL when a module completes, rather than trying to use the browserstack REST API to change the URL, which had constant errors for little to no reason. Even if it did work though, it was significantly slower.
• linting is more accurate now for files in test/runner. I didn't have the order right in eslint.config.js
• sinon 7.x is the latest version that supports IE9

Sample browserstack runs on my repo:

https://github.com/timmywil/jquery/actions/runs/8118427324 https://github.com/timmywil/jquery/actions/runs/8124843564

Testing time should be around 5-10min for all 3.x browsers!

When reviewing, the first 2 commits are almost identical to the main branch versions. It's the following commits that implement changes for 3.x and new improvements.

Checklist

• [x] New tests have been added to show the fix or feature works
• [x] If needed, a docs issue/PR was created at https://github.com/jquery/api.jquery.com

[timmywil]

It uses our built-in report API to set the browser URL when a module completes, rather than trying to use the browserstack REST API to change the URL, which had constant errors for little to no reason.

Can you explain it in a bit more detail to me?

Sure, if you look at this line, notice that any response from the report function is returned in the report API response. The only times we return responses are in response to the runEnd request:

• for retrying the same test: https://github.com/jquery/jquery/pull/5427/files#diff-9d5febf25eeb90f58a863b318706a4363188314e8ca1e85ad06a187bbf0dc174R107
• for starting the next test on failure: https://github.com/jquery/jquery/pull/5427/files#diff-9d5febf25eeb90f58a863b318706a4363188314e8ca1e85ad06a187bbf0dc174R110
• for starting the next test on pass: https://github.com/jquery/jquery/pull/5427/files#diff-9d5febf25eeb90f58a863b318706a4363188314e8ca1e85ad06a187bbf0dc174R124

listeners.js handles the response by taking the test URL and setting the window location.

Trying to use BrowserStack's REST API to change the URL on the worker was slower and incredibly error-prone.

[timmywil]

I've incorporate the feedback in #5428 as well.