[DO NOT MERGE] Remove platform tests running on Alpine Linux

[xuganyu96]

Alpine Linux is not listed in PLATFORMS.md, and the CI pipeline over in the ci-containers repository does not automatically build/push the Alpine Linux CI image. Perhaps it is time to sunset this set of tests.

See #2304 and ci-containers issue 78

• [NO] Does this PR change the input/output behaviour of a cryptographic algorithm (i.e., does it change known answer test values)? (If so, a version bump will be required from x.y.z to x.(y+1).0.)
• [NO] Does this PR change the list of algorithms available -- either adding, removing, or renaming? Does this PR otherwise change an API? (If so, PRs in fully supported downstream projects dependent on these, i.e., oqs-provider will also need to be ready for review and merge by the time this is merged. Also, make sure to update the list of algorithms in the continuous benchmarking files: .github/workflows/kem-bench.yml and sig-bench.yml)

[baentsch]

That's a bit "drastic": Have you checked we don't lose test coverage with this change? If we'd do, a better approach would be to replace ci-alpine-amd64 with ubuntu:latest, no?

[xuganyu96]

That's a bit "drastic": Have you checked we don't lose test coverage with this change? If we'd do, a better approach would be to replace ci-alpine-amd64 with ubuntu:latest, no?

I agree with this assessment. I will edit the PR to indicate that this is not meant to be merged, only for evaluation purposes only.

[coveralls]

coverage: 83.584% (-0.003%) from 83.587%
when pulling f65eba2 on gyx-sunset-alpine-platform-test
into 52169a1 on main.