Ensure test class internal linkage for certain template-test types

[DNKpp]

As already reported on the official discord, there exists a severe issue with TEMPLATE_LIST_TEST_CASE_METHOD .

Hi, one of our Devs stumbled across a severe issue with catch. We recently started using TEMPLATE_LIST_TEST_CASE_METHOD in multiple TUs. Unfortunately, catch does not define it's internal CATCH2_INTERNAL_TEMPLATE_TEST_ class in an anonymous namespace, which then leads to UB. We just saw that, because one test-case always executes the body of another test-case from another TU. As a workaround we defined each such test-case in an explicit anonymous namespace, which fixes the problem.

When fixing that I found a similar issue with TEMPLATE_PRODUCT_TEST_CASE_METHOD.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.30%. Comparing base (195231c) to head (b9b1296).

Additional details and impacted files

@@            Coverage Diff             @@
##            devel    #3161      +/-   ##
==========================================
+ Coverage   91.26%   91.30%   +0.03%     
==========================================
  Files         204      204              
  Lines        8905     8905              
==========================================
+ Hits         8127     8130       +3     
+ Misses        778      775       -3     

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[horenmar]

Thanks