Revert D113962248: Optimizer scratch-buffer stashing in MemoryStashingManager (#4495) - #4495

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v4, actions/setup-python@v5. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Unexpected input(s) 'packages', valid inputs are ['python-version', 'python-version-file', 'cache', 'architecture', 'check-latest', 'token', 'cache-dependency-path', 'update-environment', 'allow-prereleases', 'freethreaded']