Function objectMetaMap

Like objectMap, but at the reflective level of property descriptors rather than property values.

Except for hardening, the edge case behavior is mostly the opposite of the objectMap edge cases.

• No matter how mutable the original object, the returned object is hardened.
• All own properties of the original are mapped, even if symbol-named or non-enumerable.
• If any of the original properties were accessors, the descriptor containing the getter and setter are given to metaMapFn.
• The own properties of the returned are according to the descriptors returned by metaMapFn.
• The returned object will always be a plain object whose state is only these mapped own properties. It will inherit from the third argument if provided, defaulting to Object.prototype if omitted.

Because a property descriptor is distinct from undefined, we bundle mapping and filtering together. When the metaMapFn returns undefined, that property is omitted from the result.