Refactor binary to decimal conversion tests for clarity and organization

[Imran-imtiaz48]

No description provided.

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

If this PR does not affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), please add the following to the merge-commit message which will stops student's tests from re-running. Please copy-paste to avoid typos.

[no important files changed]

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[ryanplusplus]

Hey @Imran-imtiaz48 these tests are separate so that they track the canonical tests defined in the upstream problem-specifications repo. Additionally, having separate tests means that all failures are reported, not just the first failed check in a long super test.