Preserve arm64v8/alpine for arm64 runners

Chain the ternary conditions instead of grouping them so that arm64
runners keep using arm64v8/alpine while IDC runners use the public
alpine image.

Author: scotts

.github/workflows/linux_job_v2.yml

@@ -308,13 +308,13 @@ jobs:
         uses: ./test-infra/.github/actions/chown-directory
         with:
           directory: ${{ github.workspace }}/${{ env.repository }}
-          ALPINE_IMAGE: ${{ (startsWith(inputs.runner, 'linux.arm64') || startsWith(inputs.runner, 'linux.idc')) && 'alpine' || '308535385114.dkr.ecr.us-east-1.amazonaws.com/tool/alpine' }}
+          ALPINE_IMAGE: ${{ startsWith(inputs.runner, 'linux.arm64') && 'arm64v8/alpine' || startsWith(inputs.runner, 'linux.idc') && 'alpine' || '308535385114.dkr.ecr.us-east-1.amazonaws.com/tool/alpine' }}
 
       - name: Chown runner temp
         uses: ./test-infra/.github/actions/chown-directory
         with:
           directory: ${{ runner.temp }}
-          ALPINE_IMAGE: ${{ (startsWith(inputs.runner, 'linux.arm64') || startsWith(inputs.runner, 'linux.idc')) && 'alpine' || '308535385114.dkr.ecr.us-east-1.amazonaws.com/tool/alpine' }}
+          ALPINE_IMAGE: ${{ startsWith(inputs.runner, 'linux.arm64') && 'arm64v8/alpine' || startsWith(inputs.runner, 'linux.idc') && 'alpine' || '308535385114.dkr.ecr.us-east-1.amazonaws.com/tool/alpine' }}
 
       - name: Prepare artifacts for upload
         if: always()