build: align test save location configs

[yangannyx]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:
CircleCI can't detect previous test timing data. Fixing this by tweaking the script we use to ensure filepaths in the junit xml files are using relative paths
Testing:

• Tested that running the new script for making test paths relative works on a test xml file generated locally using CI=1 yarn test --suite="slow"
• Checking CircleCI Run Slow Tests output to ensure that circle was able to autodetect file timings

[dsanders11]

Looks like it's still having trouble with Windows.

[DevanceJ]

Thank you for this!

[yangannyx]

I just merged main with no additional changes to the previous, and surprisingly filename timings across all platforms were detected. This makes me think that the timing detection issue we saw on the previous slow Windows CI run wasn't caused by outputting OS incompatible relative paths. My theory right now is that the path detection relies on testing output from previous circle runs. I wish I could ssh into the circle testing machines to confirm the content of the test folder and get a better mental model, but it looks like Rerun with SSH is disabled.

I want to confirm the following:

1. Is filename timing detection broken on main? To test this I will 1a (commit). comment out the current logic changes to generating the relative paths and set a new folder path for CI runs to store test data in. This will hopefully prevent interference from other CI builds on other PRs. Then I will 1b (commit). make an inconsequential change and see if the test output from the previous commit detects filename timing. If commit 1b succeeds, I don't think there's an issue on main.
2. If commit 1b fails, I will retry 1a and 1b but with the relative path replacement changes I made. I'll see where this takes me