Deduplicate common tests part1

[scpeters]

🎉 New feature

Deduplicate some code in common tests

Summary

This is a prototype of some deduplication of code in the common tests:

• adf1147: reference feature lists recursively to avoid repeating feature names
• af8e428: add templatized helper function for requesting engine and loading an empty world and replace duplicate code in all test cases. Some additional helper functions could be added to further reduce the code duplication.

Test it

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #448 (af8e428) into gz-physics6 (619625d) will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           gz-physics6     #448   +/-   ##
============================================
  Coverage        75.73%   75.73%           
============================================
  Files              140      140           
  Lines             7039     7039           
============================================
  Hits              5331     5331           
  Misses            1708     1708           

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