[CMAKE] Add a check-upgrade-activated magic target

Summary:
This target will run the tests with the next upgrade activated. For now
it only runs the unit tests.
This removes the tests with upgrade from the check-all target.

Depends on D4799.

Test Plan:

ninja check-upgrade-activated

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D4800