[Breaking change] For dotnet test, switch -a to alias --arch instead of --test-adapter-path

[richlander]

Check it out ...

rich@MacBook-Air-M1-2020 tests % dotnet test --help | grep -- -a
  -a, --test-adapter-path <ADAPTER_PATH>  The path to the custom adapters to 
  --blame-crash-collect-always            Enables collecting crash dump on 
  <blame-crash-collect-always>            expected as well as unexpected 
  --arch <arch>                           The target architecture.
rich@MacBook-Air-M1-2020 tests % dotnet run --help | grep -- -a
  -a, --arch <arch>                    The target architecture.

Sure would be nice to make -a the same everywhere. I doubt that the current usage of -a is common.

This is similar to #21952.

• https://grep.app/search?q=dotnet%20test%20-a
• https://grep.app/search?q=dotnet%20test%20--test-adapter-path

[sfoslund]

@nohwnd for the dotnet test team

[nohwnd]

If we are breaking this, that we should probably consider using -r for --runtime, instead of --results-directory. And also check if there are more conflicts with dotnet test.