ci: remove aarch64 build (#34178)

remove

.github/workflows/selfdrive_tests.yaml

@@ -75,14 +75,8 @@ jobs:
         ${{ env.RUN }} "scripts/lint/lint.sh --skip check_added_large_files"
 
   build:
-    strategy:
-      matrix:
-        arch: ${{ fromJson(
-           ((github.repository == 'commaai/openpilot') &&
-              ((github.event_name != 'pull_request') ||
-               (github.event.pull_request.head.repo.full_name == 'commaai/openpilot'))) && '["x86_64", "aarch64"]' || '["x86_64"]' ) }}
     runs-on:
-     - ${{ ((matrix.arch == 'aarch64') && 'namespace-profile-arm64-2x8') || ((matrix.arch == 'x86_64') && ((github.repository == 'commaai/openpilot') && ((github.event_name != 'pull_request') || (github.event.pull_request.head.repo.full_name == 'commaai/openpilot'))) && 'namespace-profile-amd64-8x16') || 'ubuntu-24.04'}}
+     - ${{ ((matrix.arch == 'x86_64') && ((github.repository == 'commaai/openpilot') && ((github.event_name != 'pull_request') || (github.event.pull_request.head.repo.full_name == 'commaai/openpilot'))) && 'namespace-profile-amd64-8x16') || 'ubuntu-24.04'}}
      - ${{ ((matrix.arch == 'x86_64') && ((github.repository == 'commaai/openpilot') && ((github.event_name != 'pull_request') || (github.event.pull_request.head.repo.full_name == 'commaai/openpilot'))) && 'namespace-experiments:docker.builds.local-cache=separate' || 'ubuntu-24.04') }}
     steps:
     - uses: actions/checkout@v4
@@ -92,7 +86,7 @@ jobs:
       if: github.ref == 'refs/heads/master' && github.event_name != 'pull_request' && github.repository == 'commaai/openpilot'
       run: |
         echo "PUSH_IMAGE=true" >> "$GITHUB_ENV"
-        echo "TARGET_ARCHITECTURE=${{ matrix.arch }}" >> "$GITHUB_ENV"
+        echo "TARGET_ARCHITECTURE=x86_64" >> "$GITHUB_ENV"
         $DOCKER_LOGIN
     - uses: ./.github/workflows/setup-with-retry
     - uses: ./.github/workflows/compile-openpilot
@@ -123,23 +117,6 @@ jobs:
     - name: Building openpilot
       run: . .venv/bin/activate && scons -j$(nproc)
 
-  docker_push_multiarch:
-    name: docker push multiarch tag
-    runs-on: ubuntu-latest
-    if: github.ref == 'refs/heads/master' && github.event_name != 'pull_request' && github.repository == 'commaai/openpilot'
-    needs: [build]
-    steps:
-    - uses: actions/checkout@v4
-      with:
-        submodules: false
-    - name: Setup docker
-      run: |
-        $DOCKER_LOGIN
-    - name: Merge x64 and arm64 tags
-      run: |
-        export PUSH_IMAGE=true
-        scripts/retry.sh selfdrive/test/docker_tag_multiarch.sh base x86_64 aarch64
-
   static_analysis:
     name: static analysis
     runs-on: