Skip System.Security.Cryptography.OpenSsl.Tests on Apple platforms and Android

[Copilot]

The System.Security.Cryptography.OpenSsl.Tests were running locally on macOS and Android when developers executed ./build.sh -rc release -s libs.tests -test, even though these tests will always fail due to the removal of OpenSSL compatibility from Apple platforms and Android.

While the tests were already excluded from CI builds via the IgnoreForCI condition in the project file, they would still run (and fail) in local development environments on these platforms.

This change adds an AssemblyInfo.cs file to the OpenSsl tests project with an assembly-level SkipOnPlatform attribute:

[assembly: SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst | TestPlatforms.Android, 
    "OpenSSL is not supported on Apple platforms and Android")]

Additionally, the IgnoreForCI condition in the project file has been updated to include MacCatalyst, ensuring consistency between the CI exclusions and the runtime test skipping.

This ensures that when tests are run locally on any of these platforms, the entire test assembly is skipped with a clear message explaining why. The solution follows the same pattern used by other libraries in the codebase (such as System.IO.Pipes and System.Net.Security).

The tests continue to run normally on Linux and other supported platforms where OpenSSL is available.

Fixes #118865.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Copilot]

Pull Request Overview

This PR improves the developer experience by ensuring that System.Security.Cryptography.OpenSsl.Tests are properly skipped on platforms where OpenSSL is not supported, rather than running and failing. The change addresses the issue where tests would run locally on macOS and Android despite being excluded from CI builds.

Key changes:

• Adds assembly-level platform skipping for unsupported platforms using Xunit's SkipOnPlatform attribute
• Updates CI exclusion conditions to include MacCatalyst for consistency

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/libraries/System.Security.Cryptography.OpenSsl/tests/System.Security.Cryptography.OpenSsl.Tests.csproj	Added MacCatalyst to the IgnoreForCI condition
src/libraries/System.Security.Cryptography.OpenSsl/tests/AssemblyInfo.cs	New file with assembly-level SkipOnPlatform attribute for unsupported platforms

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-security, @bartonjs, @vcsjones
See info in area-owners.md if you want to be subscribed.

[vcsjones]

@copilot the new file you added, AssemblyInfo.cs, is not in System.Security.Cryptography.OpenSsl.Tests.csproj so it won't be included as part of compilation. Can you please add this file to the top of the <ItemGroup> that includes source files?

[Copilot]

@copilot the new file you added, AssemblyInfo.cs, is not in System.Security.Cryptography.OpenSsl.Tests.csproj so it won't be included as part of compilation. Can you please add this file to the top of...

Added AssemblyInfo.cs to the compilation ItemGroup at the top of the source files section. The file is now properly included in the build. (12fdcdd)