build: fix GHA arm tests (#42514)

.github/workflows/build.yml

@@ -159,7 +159,7 @@ jobs:
       build-runs-on: aks-linux-large
       test-runs-on: aks-linux-arm-medium
       build-container: '{"image":"ghcr.io/electron/build:${{ inputs.build-image-sha }}","options":"--user root","volumes":["/mnt/cross-instance-cache:/mnt/cross-instance-cache"]}'
-      test-container: '{"image":"ghcr.io/electron/test:arm32v7-${{ inputs.build-image-sha }}","options":"--user root --privileged --init"}'
+      test-container: '{"image":"ghcr.io/electron/test:arm32v7-${{ inputs.build-image-sha }}","options":"--user root --privileged --init","volumes":["/home/runner/externals:/mnt/runner-externals"]}'
       target-platform: linux
       target-arch: arm
       is-release: false

.github/workflows/pipeline-segment-electron-test.yml

@@ -41,6 +41,10 @@ jobs:
       BUILD_TYPE: ${{ matrix.build-type }}
       TARGET_ARCH: ${{ inputs.target-arch }}
     steps:
+    - name: Fix node20 on arm32 runners
+      if: ${{ inputs.target-arch == 'arm' }}
+      run: |
+        cp $(which node) /mnt/runner-externals/node20/bin/
     - name: Checkout Electron
       uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
       with: