[VMR] Build tests in certain CI configurations in the VMR

[mmitche]

Right now, Linux source build does not build repo test projects in the VMR. This is not necessary for producing the assets required for shipping to Linux distro partners (or their customers). This significantly speeds up the build, as well as avoids introducing any unwanted prebuilts.

We need to determine how test projects fit into the VMR vertical builds for .NET 9.

Initial thoughts:

• VMR PR legs need to build the test projects. Breaking changes within the product may need test updates. #4169
• Rolling CI builds should build the test projects, to validate that things still build on the merged content #4168
• Official builds should not build the test projects, with the exception of the scenario tests.

T-Shirt size for implementation: XS

[mmitche]

I believe the thoughts above would suffice.

T-Shirt size for implementation: Small

[MichaelSimons]

What work remains here? The plan is captured here. Bullets two and three need to be implemented. Is this issue intended to track the implementation as well? Asking in relation to #4163.

cc @mmitche, @ViktorHofer.

[ViktorHofer]

windows x64, linux x64 and osx x64 shoudl initially be sufficient.

[mmitche]

We should close this an keep the other open IMO

[mmitche]

Made this an epic and opened issue for the two uncompleted bullets. The official builds already avoid tests.

[ViktorHofer]

Pull Request: dotnet/sdk#44843