feat: add support for @TestTarget annotation for junit tests written in scala

[psliwa]

When junit test is written in scala @TestTarget annotation attached to val doesn't work because of:

java.lang.IllegalAccessException: class kotlin.reflect.jvm.internal.calls.CallerImpl$FieldGetter cannot access a member of class au.com.dius.pact.provider.junit.ScalaJunitTest with modifiers "private final"

In scala if you define class member by val x it will be represented in bytecode by private field x and public getter method x(). Because of this implementation detail it is not possible to use @TestTarget annotation on scala's val x = ... class member.