Checks if `value` is likely a prototype object.

@private
@param {*} value The value to check.
@returns {boolean} Returns `true` if `value` is a prototype, else `false`.
function isPrototype(value) {
  var Ctor = value && value.constructor,
      proto = typeof Ctor == 'function' && Ctor.prototype || objectProto$1;

  return value === proto;
}