[PLAT-6748] Disable americanTest

Disabling `americanTest` as it is not passing - it has not generally been run before as it is part of the `UNIT_SLOW` test group.

This enables the tests to be run for the `UNIT` and `UNIT_SLOW` test groups without any failures.
Can you add a "description =" to the annotation stating the date it was disabled and reason (which is that t doesn't pass).