Report all fires of window.onerror.

Additionally, mark the test as having results so that it
won't be ran again. The reported URL is simplified if possible.
Use actual URL if shorter URL not available.
Do not advance to the next test on scriptError.

Often these errors will not impact the completion of the test.
If they do, the timeout will catch it.
Provide proper URL for scriptError.
Merge pull request #31 from reid/fix-onerror

Report all fires of window.onerror.