[circt-test] fix SymbiYosys integration test

[unlsycn]

#7756 adds the SymbiYosys test runner and requires the sby feature, but did not add the corresponding available feature in lit.cfg.py, so this test never seems to run, and #7763 introduces a syntax error, a backslash in the f-string expression part, in the Python script.
Unlike #7884, there is no need to modify PATH variable for the script since sby should be in the PATH if we can check it in CMake.

[unlsycn]

cc @fabianschuiki

[unlsycn]

https://github.com/llvm/circt/actions/runs/11998261862/job/33447711728#step:5:330
It looks like we should add Symbiyosys for https://github.com/circt/images/tree/trunk/integration_test

[fabianschuiki]

Good thinking! We should definitely add SymbiYosys to the set of tools installed for integration tests.

[fabianschuiki]

LGTM! Thanks a lot for fixing this!

[fabianschuiki]

If you would like to land this yourself once CI passes, feel free to obtain commit access to LLVM. Otherwise let me know and I can merge things for you 😃

[fabianschuiki]

@unlsycn I have added SymbiYosys and a more up-to-date build of Yosys to the integration test CI image (v18.0) in #7895. I'll land that in a few minutes if CI passes. Once that's in main, you could try to rebase this PR onto main and see if the integration test CI picks up the SymbiYosys installation and the test you fixed here now runs 🙂

[fabianschuiki]

It looks like something might be broken in the integration image's sby setup 😞, sorry about that. This is going to be a bit annoying to debug. One approach could be to tweak the circt-test-runner-sby.py file to not just say "see xyz.log", but to make it read and print that xyz.log. That would allow us to see the sby output log in the GitHub action.