Add tests for heap bins small, large and unsorted cmd

Description/Motivation/Screenshots

This PR adds some missing tests for:

• heap bins small
• heap bins large
• heap bins unsorted

All 3 new tests use the same binary file heap-bins.out.

How Has This Been Tested?

Checklist

• My PR was done against the dev branch, not master.
• My code follows the code style of this project.
• My change includes a change to the documentation, if required.
• My change adds tests as appropriate.
• I have read and agree to the CONTRIBUTING document.