Revert "implement `@expect` builtin (#19658)"

This reverts commit a7de02e05216db9a04e438703ddf1b6b12f3fbef.

This did not implement the accepted proposal, and I did not sign off
on the changes. I would like a chance to review this, please.
9be8a9000fAndrew Kelley committed on 5/22/2024, 4:57:43 PMparenta7de02e
25 files changedLine totals unavailable