Add a new test for a helper function in the test framework (added in D8852)
Introduce a new prefix for functional tests: `framework_test`
This concludes backport of Core [[https://github.com/bitcoin/bitcoin/pull/18378 | PR18378]]
https://github.com/bitcoin/bitcoin/pull/18378/commits/a733ad514a172a77309b84cbc6c81562bdf12e28
Depends on D8852