[JUnit5] Inject list of forgeries

[xgouchet]

In a Junit5 test, it would be nice to be able to write (assuming a Forgery of Foo is available) :

``
`
class A {
@forgery lateinit var fakeList : List

@Test
fun test(@Forgery list : List<Foo>) {
    // …
}

}
`
``