SciPy XSLOW tests *extremely* slow

Has anyone recently run the full test suite locally with the XSLOW tests included? Sometime in the last week or so it went from “extra” slow to “extremely” slow. I’ll look into which tests have recently been changed or added, but chime in if you already know what changed.

It appears to be the result of ENH: special: add more functions to `_support_alternative_backends` by NeilGirdhar · Pull Request #22795 · scipy/scipy · GitHub.

Github issue: BUG/TST: special: An XSLOW test appears to hang. · Issue #23363 · scipy/scipy · GitHub.