Move some test coverage explicitly to code

[yezr]

In a comment on #913 @artoonie gave an example of tests that make explicit changes to a shared file that is then retested. This addresses a concern that a minor change to an already existing test, done by changing the CVR data itself, could get undone in future updates. This type of test makes more explicit what is being tested.

This issue is for implementing that type of test for unprintable characters in the castVoteRecord.getId() and ensuring that it shows up properly in the audit.log and rctab_cvr per #911.