BTMP chunks in packfiles break WAL object repacking tests
We have recently introduced support for repacking objects in the write-ahead log. The accommodating tests are broken with Git's master
branch. Bisecting the breakage leads to 5f5ccd9595 (midx: implement BTMP chunk, 2023-12-14).
The root cause is that we assert static hashes in the tests, but the above commit changed the on-disk format that changes those hashes.