Test that uncaught exceptions will be reported to the window.onerror handler. Bug 8519.

Main frame window.onerror: Uncaught Error: Inline script exception at window-onerror2.html:34
Main frame window.onerror: Uncaught Exception in onload at window-onerror2.html:2
Main frame window.onerror: Uncaught Error: Exception in setTimeout at window-onerror2.html:29

