Tests the properties of the XMLHttpRequestException object.

PASS e.toString() is "Error: NETWORK_ERR: XMLHttpRequest Exception 101"
PASS Object.prototype.toString.call(e) is "[object XMLHttpRequestException]"
FAIL Object.prototype.toString.call(e.__proto__) is not "[object XMLHttpRequestException]". Was "[object XMLHttpRequestExceptionPrototype]"
PASS e.constructor.toString() is "[object XMLHttpRequestExceptionConstructor]"
PASS e.constructor is window.XMLHttpRequestException
PASS e.NETWORK_ERR is e.constructor.NETWORK_ERR
PASS e.NETWORK_ERR is 101