Keyword suggestion: prevent shadowing properties in Object.prototype

Hi, a variant of "propertyNames" keyword could strip property names in Object.prototype. It could be a fast version with a `key in Object.prototype` check, and I'd like to use it whenever I allow additionalProperties. The reason I'm suggesting this is that currently quite often people just use `JSON.parse` and don't consider that if they get a malicious object such as `{"toString":null}` it will quite easily break downstream as some logging, string concatenation or similar will call `toString` on it. Similar with other properties in `Object.prototype`, and it would be nice to avoid the function call in "propertyNames" with this keyword variant.