In two PRs nightly build report strange error on fuzzy tests which is (a) unrelated to the code changes and (b) I can't understand. I assume master also got broken.

• https://github.com/rust-bitcoin/rust-bitcoin/pull/666/checks?check_run_id=3718558662#step:5:2501
• https://github.com/rust-bitcoin/rust-bitcoin/pull/646/checks?check_run_id=3717024631#step:5:2501