Switch to cross build for Alpine

[richlander]

The Alpine build should switch to cross-build, like is done in dotnet/runtime.

Existing pattern:

diagnostics/eng/pipelines/pipeline-resources.yml

Line 34 in 055897a

image: mcr.microsoft.com/dotnet-buildtools/prereqs:alpine-3.13-WithNode

Correct pattern:

https://github.com/dotnet/runtime/blob/564609591ac7ae7fdc87f69419b80308e1f1bef4/eng/pipelines/common/templates/pipeline-with-resources.yml#L36

We shouldn't be using old Alpine images.

The Azure Linux cross-build targets Alpine 3.13, so there is no loss in targeting. However, the newer image uses a much newer clang. As we discovered before (#4556), it will take some effort to make this repo compatible with a new toolset.

@mikem8361 @sbomer @hoyosjs

[mikem8361]

Should the diagnostics repo be using the azurelinux-3.0-* (instead of the current cbl-mariner-2.0-*) images for linux_arm, linux_arm64, linux_musl_arm, linux_musl_arm64, etc.?

For linux_x64 we are using mcr.microsoft.com/dotnet-buildtools/prereqs:centos-7 since SOS, etc. needs to run on older linux distros. Can we use mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-amd64-net8.0 like the runtime?

[richlander]

We should continue using centos-7 for .NET 6 compat. That's what we're using everywhere else. You can move to azurelinux-3.0-cross-amd64-net8.0 once .NET 8 is the lowest version you need to support.

Yes, for now, the cbl-mariner images are a better choice. Once that is in place, we can move you to the azurelinux images pretty easily once the time is right (which will be within the next few months).