github: add risky to next workflow

Author: colemickens

.github/workflows/next.yaml

@@ -53,6 +53,7 @@ jobs:
         sudo determinate-nixd upgrade --tools branch/main --daemon branch/main
     - uses: "DeterminateSystems/magic-nix-cache-action@main"
     - name: build + cache
+      if: ${{ success() || failure() }}
       run: |
         ulimit -a
         nix flake check --keep-going --build-all -L
@@ -62,3 +63,13 @@ jobs:
         # run it again, hopefully this time the output is easier to read
         ulimit -a
         nix flake check --keep-going --build-all -L
+    - name: build + cache (jupitertwo)
+      if: (success() || failure()) && matrix.runner == 'ubuntu-24.04'
+      run: |
+        nix build -L --keep-going \
+          .#toplevels.jupitertwo
+    - name: build + cache (riscv64 iso bits)
+      if: (success() || failure()) && matrix.runner == 'ubuntu-24.04'
+      run: |
+        nix build -L --keep-going \
+          .#extra.riscv64-linux.installer