1 Tests if repeated loading of non-existent img.src resources doesn't deliver onload.
3 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
6 PASS Received onerror for non-existent img.src
7 PASS Received onerror for non-existent img.src
8 PASS Received error event repeatedly.
9 PASS Received onload for broken img.src
10 PASS successfullyParsed is true