Overwrite ILLinkTasksAssembly

[ViktorHofer]

If the Microsoft.NET.ILLink.Tasks package is package referenced directly, overwriting ILLinkTasksAssembly guarantees that the SDK uses the right ILLink assembly. Github org searches didn't show any consumer of the private properties, hence removing them for simplification.

dotnet/arcade#6936 benefits from this change.

[sbomer]

We shouldn't get rid of the '$(ILLinkTasksAssembly)' == '' condition - that's useful for testing against a local build of the linker.

[ViktorHofer]

For local builds, ILLinkTasksAssembly can still be passed in globally which always takes precedence and overwrites any values set here, i.e. dotnet build /p:ILLinkTasksAssembly=x\ILLink.Tasks.dll

[sbomer]

I typically like to set it in the project file rather than the command-line.

[ViktorHofer]

That still works as props are imported before the project file which means that the value in the project file overwrites what is in the props file (as long as the property isn't passed in globally).

[sbomer]

The Sdk.props are imported late in https://github.com/dotnet/sdk/blob/master/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets#L14. Should that be changed?

[ViktorHofer]

oh forget that. yes, we should definitely fix that as props should be imported before the project is evaluated.

[ViktorHofer]

Either via a ILLink.props file in the SDK (which then is imported by Microsoft.Net.Sdk.props) or directly in the Microsoft.Net.Sdk.props file.

[ViktorHofer]

@sbomer should I take care of that or do you want to?

[sbomer]

I will take care of it, thanks!