unwrapIfReflectionCall

In some particular cases, such as AnnotationSpec, a call will be made using Reflection. When using reflection, any error will be wrapped around a InvocationTargetException, as explained in https://stackoverflow.com/questions/6020719/what-could-cause-java-lang-reflect-invocationtargetexception By verifying if this is an InvocationTargetException, we can unwrap it and throw the cause instead