Missing 8.0 build images (Azure Linux 3.0)

[richlander]

The following images are missing:

• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-android-amd64-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-android-amd64-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-android-docker-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-amd64-net8.0-sanitizer
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-ppc64le-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-riscv64-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-webassembly-amd64-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-cross-freebsd-13-net8.0
• mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-fpm-net8.0

They exist for 9.0/main, but not for the 8.0 branch (at the time of writing):

• https://github.com/dotnet/runtime/blob/main/eng/pipelines/common/templates/pipeline-with-resources.yml
• https://github.com/dotnet/runtime/blob/release/8.0-staging/eng/pipelines/common/templates/pipeline-with-resources.yml

@sbomer

[lbussell]

[Triage] When fixing this, please keep in mind #1176

[sbomer]

We don't have a sanitizer leg for net8.0, so that one isn't needed.