ci/eval/compare: set NixOS test rebuild label on all PRs that do so (#512914)

            kernel: rebuilds: lib.nameValuePair "10.rebuild-${kernel}-stdenv" (lib.elem "stdenv" rebuilds)

          ) rebuildsByKernel

          // {

            "10.rebuild-nixos-tests" =

              lib.elem "nixosTests.simple" (extractPackageNames diffAttrs.rebuilds)

              &&

                # Only set this label when no other label with indication for staging has been set.

                # This avoids confusion whether to target staging or batch this with kernel updates.

                lib.last (lib.sort lib.lessThan (lib.attrValues rebuildCountByKernel)) <= 500;

            "10.rebuild-nixos-tests" = lib.elem "nixosTests.simple" (extractPackageNames diffAttrs.rebuilds);

          };

      }

    );