Drop non-toolchain package checks to optional status

[jeremy@…]

For non-toolchain packages, drop the tests on them to an optional status. Adjustments to allow those tests to run should stay in the book, but the tests themselves should be listed in the instructions as optional:

"This package has a testsuite available which can perform a number of checks to ensure it built correctly. Should you choose to run it, the following command will do so:"