Before, Object.prototype was {} — tests writing
Object.prototype.hasOwnProperty.call(o, 'x') failed with 'TypeError: call
is not a function' because hasOwnProperty was undefined on the prototype.
Now Object.prototype.hasOwnProperty / .isPrototypeOf / .propertyIsEnumerable
/ .toString / .toLocaleString / .valueOf all exist. They dispatch on
(js-this) so Array.prototype.X.call-style calls work.
Unblocks String.prototype.* tests that set up '__instance = new Object(true)'
and then probe __instance.hasOwnProperty.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>