[17.0.2] Aggressive cleanup to assist garbage collection

[amadeus]

Re-applying the fixes from react 16 onto 17, courtesy of paulshen#2

If you'd like to use this in your code, simply set react-dom version to: discord/react#e208b3186d89b0d8394cc23f09ea6b95de84affd in your package.json

[levellearning-admin]

Thank you so much for maintaining this!