nightly: Add regression test for #2718: `/[]*1/u.exec()` should not panic (#4726)

This Pull Request fixes/closes #2718.

It changes the following:
- Adds a regression test for `/[]*1/u.exec()` to ensure it returns
`null` and does not panic
- The panic was caused by a bug in the `regress` crate
(ridiculousfish/regress#99), fixed upstream in October 2024 and resolved
in the version Boa currently uses (0.10.5)