Prepare for testing multiple ISAs in CI

[jordancarlin]

Update matrix structure and add sed commands to change the extensions being tested. Going forward all that needs to be done to test different sets of extensions is add an entry to the matrix.

[UmerShahidengr]

I doubt this approach will work. We are trying to improve the CI to run multiple extensions and different architecture configurations, like e.g, we want to run misaligned_load tests (in privilege folder) twice, once with misaligned support enabled on both Spike and Sail, and once with misaligned support disabled for both, similarly there will be alot of other tests in future which will require to be run twice based on different configuration options. Such options cannot be passed via CI so we require multiple files in which we will change the configuration flags and manage those files. CI will take those files and run it.
Your work, although is brilliant, but will greatly complicate the CI, my recommendation would be to keep CI simple, and execute a bunch of files in the CI, and maintain those files for longer run to enable/disable the extension and/or to add more sail/spike configuration options running ACTs

[jordancarlin]

That makes sense to me. Was trying to keep it simple and avoid needing lots of different files, but I missed that there will be some parameters that need to be changed that are outside of the scope of the isa string. Maintaining separate configuration files will be simpler in that case.