Promises incorrectly reject with DOM `Event`, not `Error`.

[mik3y]

Certain sites, such as these in useScriptTag, reject errors with an Event object, not an Error.

We see this causing errors like Event Event (type=error) captured as promise rejection in our global uncaught exception handler, e.g. when a script load is interrupted.

[childrentime]

#184 try version v6.1.7 @mik3y