Whether redefining Property on Type should keep the property mutable when
the new attribute doesn't say either way. This mirrors Object.defineProperty(),
which keeps a property's existing writable flag when it isn't part of the new
descriptor and the property already exists.
Whether redefining
PropertyonTypeshould keep the property mutable when the new attribute doesn't say either way. This mirrorsObject.defineProperty(), which keeps a property's existingwritableflag when it isn't part of the new descriptor and the property already exists.