Fix placeholder cache reuse across backend switches - #238

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v3, actions/setup-java@v3, gradle/gradle-build-action@v2. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Failed to restore v8-gradle|Linux|pr tests-build[37a6259cc0c1dae299a7866489dff0bd]-d9b3c8b375219907ac669a852d3f3a19360ec39b: Error: Cache service responded with 400