Post-release test improvements

[agateau-gg]

Context

Following a failure in the MatchSpan test during the 1.29.0 release, I made a few improvements and cleanup. Still got some HMSL test fixes to do, but that will be done in a separate PR.

What has been done

• Fix MatchSpan test
• Remove obsolete cassettes

Validation

Tests still pass.

PR check list

• [x] As much as possible, the changes include tests (unit and/or functional)
• [x] If the changes affect the end user (new feature, behavior change, bug fix) then the PR has a changelog entry (see doc/dev/getting-started.md). If the changes do not affect the end user, then the skip-changelog label has been added to the PR.