Sync strain tests

[BNAndras]

Related to #1597. Mark as tiny.

The test suite uses slightly different functions so I updated those to match what's happening in the problem specifications. There shouldn't be any meaningful differences there. I also changed the words to be an array literal so it's a little clearer what's actually being compared before and after. That included a minor typo fix. Finally, I added two missing tests for keeps nothing and discards nothing

[github-actions]

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[BNAndras]

Hmm, I thought defining the predicates outside the function call like we did over in Accumulate would fix the @typescript-eslint/no-unused-vars error.

[SleeplessByte]

Hmm, I thought defining the predicates outside the function call like we did over in Accumulate would fix the @typescript-eslint/no-unused-vars error.

Nah, I set it up that we must prefix with _. I want us to be explicit about unused variables!

[BNAndras]

Makes sense. :)