[5.x] Add failing test for issue caused by PR #9585

[aerni]

This PR adds a failing test to illustrate the issue caused by PR https://github.com/statamic/cms/pull/9585. That PR makes it impossible to manipulate a blueprint multiple times during the same request. This is an issue when you are relying on manipulating the blueprint at different stages in an EntryBlueprintFound listener.

Jason said: I don't see any noticeable difference in load times, but this PR is only a handful of lines now so I don't think it hurts. So, maybe it's not a big deal to revert the PR altogether?

Else, we might need to find a way to opt-out of the fields cache. Or maybe this is simply a bug that can be fixed while retaining the caching.