Improvements to `dotnet test` in .NET9

So far, the preview versions of .NET 9 have introduced two improvements to the dotnet test command.

• 💅 The output logs will use the new terminal logger by default, resulting in a better experience with more clearly arranged output. The terminal logger was introduced in .NET 8 as an opt-in alternative to the normal console logger. The new behavior uses the new terminal logger by default for environments that support this, and can be disabled using the --tl:off switch. For more information and the reasoning for this new behavior see Terminal logger is default
• 🏎️ Test projects that hit different Target Frameworks will be run in parallel. This means that you will receive the test results faster. By default the number of parallel processes will be the number of processors on the computer, it can also be configured using the -maxcpucount:N switch.

This results in a better experience for developers and faster feedback loops when running tests.

For more info about Unit Testing .NET 9 see the documentation.