Add a test to pin the 'enable default files' behavior of `dotnet run`

[baronfel]

In #50942 we removed EnableDefaultItems=false from the set of properties used to evaluate and run targets for Projects used as part of dotnet run. We did this to unblock Android use cases, where the Targets being run to compute the run command/arguments had a dependency on the default-includes behavior of the SDK. This is the safest choice for us.

However, we need to capture that expectation in a unit test so we don't regress this behavior in the future. We should create a test that dotnet run's a synthetic project with a ComputeRunArguments target that depends on a MSBuild Item that is included as part of the EnableDefaultItems=true setting. The Target could just fail if a given item wasn't found, for example.

[Youssef1313]

Let's also have a test for dotnet test if possible please :)