[infra] Disable broken linux_musl Mono AOT cross-compiler jobs in .NET 8

[ivanpovazan]

Description

After merging #105460 we discovered that both:

• linux_musl-x64 release CrossAOT_Mono crossaot and
• linux_musl-arm64 release CrossAOT_Mono crossaot

are broken jobs i.e., they never produced cross compiler packages.

Starting: Prepare job-specific intermediate artifacts subdirectory (linux_musl_x64)
==============================================================================
Task         : Copy files
Description  : Copy files from a source folder to a target folder using patterns matching file paths (not folder paths)
Version      : 2.238.0
Author       : Microsoft Corporation
Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/copy-files
==============================================================================
found 2 files
Cleaning target folder: /__w/1/a/IntermediateArtifacts/MonoRuntimePacks
Copying /__w/1/s/artifacts/packages/Release/Shipping/Microsoft.NET.Runtime.MonoTargets.Sdk.8.0.8.nupkg to /__w/1/a/IntermediateArtifacts/MonoRuntimePacks/Shipping/Microsoft.NET.Runtime.MonoTargets.Sdk.8.0.8.nupkg
Copying /__w/1/s/artifacts/packages/Release/Shipping/symbols/Microsoft.NET.Runtime.MonoTargets.Sdk.8.0.8.symbols.nupkg to /__w/1/a/IntermediateArtifacts/MonoRuntimePacks/Shipping/symbols/Microsoft.NET.Runtime.MonoTargets.Sdk.8.0.8.symbols.nupkg
Finishing: Prepare job-specific intermediate artifacts subdirectory (linux_musl_x64)

The only package they did publish is the one we disabled in #105460 so the jobs are now failing in the official build (https://dev.azure.com/dnceng/internal/_build/results?buildId=2502592&view=logs&j=a8ec8236-0fa3-5615-96d9-fad9a048e3ab&t=7c71d56b-eebb-5a41-c166-16134978d78b&l=9).

By looking back in time (to Oct-2023) these jobs never worked properly and since we did not receive any customer complaints we are just disabling them for .NET 8.

NOTE

FWIW this is properly fixed in .NET9 via: 7f81848 but was not backported.

[ivanpovazan]

@carlossanlop Could you please take a look?
This is a CI fix that is needed to get the official builds green again.

[carlossanlop]

FWIW this is properly fixed in .NET9 via: 7f81848 but was not backported

So are we planning to backport this?

[carlossanlop]

Tell-mode, approved.

[ivanpovazan]

FWIW this is properly fixed in .NET9 via: 7f81848 but was not backported

So are we planning to backport this?

I am not sure, my understand is that in .NET 8 it was a niche feature.

@directhex what do you think?