Add unmanaged assembly skipping to ILStrip task

[jkurdek]

Feeding unmanaged assembly to ILStrip resulted in task failure. This change allows ILStrip to skip unmanaged assemblies. The final list of processed assemblies is to be found at UpdatedAssemblies output. Changes to xamarin-macios will be done in separate PR.

Contributes to #101967

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[jkurdek]

cc/ @vitek-karas

[kotlarmilos]

It might be helpful to catch general failures and report them as well.

[jkurdek]

The caller of this function has a try catch block reporting all the other failures.

[steveisok]

Should this and the aot compiler task share the same way? Not intending to hold this up btw.

runtime/src/tasks/AotCompilerTask/MonoAOTCompiler.cs

Lines 615 to 621 in bbf7e8e

	using var assemblyFile = File.OpenRead(assemblyPath);
	using PEReader reader = new(assemblyFile, PEStreamOptions.Default);
	if (!reader.HasMetadata)
	{
	Log.LogMessage(MessageImportance.Low, $"Skipping unmanaged {assemblyPath} for AOT");
	continue;
	}

[vitek-karas]

If we really wanted to solve this for everybody then ILLink has the same problem and has its own solution as well. And I assume NativeAOT has it as well - but I don't know what the solution there is. Would be nice to have one solution for everybody. But I definitely don't want to block this fix on that.

[jkurdek]

I did it like this to avoid adding unnecessary overhead. I do agree it would be much nicer to have a one way of filtering the unmanaged assemblies for all the tasks. Maybe following the ILLink way and using a separate MSBuild task to filter the assemblies would be fit them all solution?

I will be merging this one so that that we can start working on xamarin-macios fix.