Fix s390x workflow to use working QEMU approach

Remove alternatives and keep only the docker/setup-qemu-action approach that works correctly.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ljharb

.github/workflows/node-s390.yml

@@ -3,8 +3,7 @@ name: 'Tests: node.js on s390x'
 on: [pull_request, push]
 
 jobs:
-  # Alternative 1: Using docker/setup-qemu-action with manual docker run
-  tests-qemu-manual:
+  tests:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
@@ -26,45 +25,3 @@ jobs:
               npm install && \
               npm run tests-only
             "
-
-  # Alternative 2: Using uraimo/run-on-arch-action (original approach)
-  tests-run-on-arch:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v5
-
-      - uses: uraimo/run-on-arch-action@v2
-        name: Run tests on s390x
-        with:
-          arch: s390x
-          distro: ubuntu22.04
-          githubToken: ${{ github.token }}
-          setup: |
-            mkdir -p "${PWD}/artifacts"
-          dockerRunArgs: |
-            --volume "${PWD}/artifacts:/artifacts"
-          install: |
-            apt-get update -q -y
-            apt-get install -q -y curl git
-            curl -fsSL https://deb.nodesource.com/setup_18.x | bash -
-            apt-get install -y nodejs
-          run: |
-            node -v
-            npm -v
-            npm install
-            npm run tests-only
-
-  # Alternative 3: Using GitHub's buildjet runners (if available)
-  tests-buildjet:
-    runs-on: buildjet-2vcpu-ubuntu-2204-arm
-    continue-on-error: true  # This might not be available for all repos
-    steps:
-      - uses: actions/checkout@v5
-
-      - name: Setup Node.js via Docker on s390x
-        run: |
-          docker run --rm --platform linux/s390x \
-            -v $PWD:/workspace \
-            -w /workspace \
-            node:18 \
-            bash -c "npm install && npm run tests-only"