test: Avoid CScript() as default function argument

Unlike other function calls in default arguments, CScript should not cause any issues in the tests, because they are const.

However, this change allows to enable the "function-call-in-default-argument (B008)" lint rule, which will help to catch severe test bugs, such as https://github.com/bitcoin/bitcoin/issues/30543#issuecomment-2259260024 .

The lint rule will be enabled in a follow-up, when all violations are fixed.