Event is logged even though it is not executed because observer got unresolvable arguments

EventContextImpl fires logs event processing and then invokes observer method:
https://github.com/arquillian/arquillian-core/blob/1.0.2.Final/core/impl-base/src/main/java/org/jboss/arquillian/core/impl/EventContextImpl.java#L99

but ObserverImpl does not invoke an observer method if it contains unresolvable argument:
https://github.com/arquillian/arquillian-core/blob/1.0.2.Final/core/impl-base/src/main/java/org/jboss/arquillian/core/impl/ObserverImpl.java#L86

We should indicate that given observer method does have unresolved argument instead.