tests/functional: Use vmstate-static-checker.py to test data from v7.2

tests/functional: Use vmstate-static-checker.py to test data from v7.2

We've got this nice vmstate-static-checker.py script that can help to
detect screw-ups in the migration states. Unfortunately, it's currently
only run manually, which can be cumbersome. Let's run it from a functional
test automatically with the reference data from QEMU 7.2, so that we get
at least a basic coverage here. Since the test can fail when the checker
script detects a false positive, mark the test with a skipFlakyTest
decorator for now, so that it is only run when the user also set the
QEMU_TEST_FLAKY_TESTS environment variable.

Acked-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250912100755.316518-5-thuth@redhat.com>