Disable what fails and blocks transitioning to Azure DevOps (dotnet/coreclr#21926)

Disable what fails and blocks transitioning to Azure DevOps (dotnet/coreclr#21926)

* Run on Debian.9.Amd64.* instead of Debian.8.Amd64.* since it's the minimum supported version of Debian

* Temporary remove Windows.10.Nano.Amd64.Open and Windows.7.Amd64.Open blocked by dotnet/coreclr#21693 dotnet/coreclr#21796

* Don't need a non-portable RHEL7 build and continue using centos7_x64_build_image for building linux-x64 packages (the same way as buildpipeline does)

* Skip submission to Helix if there is are queues to submit to

* Use static string for Helix Сreator property

* Increase timeout for official build test jobs

Commit migrated from https://github.com/dotnet/coreclr/commit/4e6ff628eaebcf32c9ea599b2d47f3290860728e