checkForPolyfills not working with latest core-js

[jlowcs]

For instance, for Array.toSorted The code seems to search for Array.prototype.toSorted, but the core-js code does not assign to Array.prototype.toSorted.

Array.prototype.toSorted is in a comment in the core-js code, but when bundling (e.g. with webpack), those comments tend to be stripped.