test onabort/ontimeout cases

[jfirebaugh]

Currently these will throw an error if they're ever triggered (undefined evt variable).

[jfirebaugh]

Hmm, according to the spec ontimeout can only be triggered if the timeout property is changed from the default of 0 (no timeout), which corslite doesn't do. onabort is triggered for abort() and possibly (?) in other cases -- the spec says "for instance".