remove redundant test helper wrappers

[0xLogicalx]

removes the common_test.go file from the zeroheavy package and updates test code to use testhelpers functions directly, aligning with the codebase convention.

[joshuacolvin0]

If you are going to remove the usage of the wrappers, you need to delete testhelpers.go as well

[github-actions]

Thank you for your contribution. However, this PR has been automatically closed because it was labeled as trivial. As stated in our CONTRIBUTING.md:

---

Important

Please, do not send pull requests for trivial changes; these will be rejected.
These types of pull requests incur a cost to reviewers and do not provide much value to the project.
If you are unsure, please open an issue first to discuss the change.
Here are some examples of trivial PRs that will most-likely be rejected:

• Fixing typos
• AI-generated code
• Refactors that don't improve usability

---

We appreciate meaningful contributions!