check required by #testFireEventWithNonRuntimeBindingTypeFails is too late

as discussed with pete this ticket is based on https://issues.apache.org/jira/browse/OWB-798

the check needed to pass org.jboss.jsr299.tck.tests.event.bindingTypes.EventBindingTypesTest#testFireEventWithNonRuntimeBindingTypeFails is slow and even more important too late.

we can do the same check (once) during bootstrapping before adding an observer.

reason why we don't need this check after bootstrapping:
if an invalid event (with an invalid qualifier) is used in a dyn. #fire, we can ignore the invalid literal-instance, because there is no corresponding observer (qualifiers of the observers would be checked during bootstrapping -> the startup would fail, if there is such an invalid observer).