Fix separate compilation tests failing under coverage

[anatoliykmetyuk]

Enable a few previously excluded scoverage tests. Some tests are compiled with older compilers to test backward compat. Those compilers do not support the scoverage flag, hence failing. The solution in this PR ensures the scoverage flag is not passed to those older compilers.

How much have you relied on LLM-based tools in this contribution?

Moderately

How was the solution tested?

Tests excluded from the excludelist pass locally. Coverage suite also passes locally.

[anatoliykmetyuk]

CI failures appear to be unrelated to the issue - main currently fails CI as well. Will rebase once main is green.

[som-snytt]

I touched something about legacy compiler and coverage.

#25452

I'm not sure offhand what is optimal.

Oh I remember I was confused because coverage is passed in as an option? So from the perspective of a test, I have no idea (by construction) whether coverage was requested.

I guess just stripping it out is the best one can do.

I'm used to test parameters being something I can see in the test code. Sometimes (like benchmark) the params are dynamic.

Edit: I guess I already commented to exclude all legacy tests from coverage...

#25452 (comment)

[anatoliykmetyuk]

Edit: I guess I already commented to exclude all legacy tests from coverage...

That could also be a solution. However, such a solution would exclude coverage data from those steps of such tests that deal with the current compiler. So I believe stripping the coverage flags based on the individual compiler versions requested is a more precise solution.