PlatformTestNode

Note, this type only exists because Kotlin does not allow yet to have a generic type with a fixed type parameter on the RHS of an actual typealias such as actual typealias PlatformTestNodeContainer = Iterable<DynamicNode> and because JUnits compatibility check at runtime requires a ParameterizedType. If JUnit would not require it but instead check if a supertype is compliant, then we could just use PlatformTestNodeContainer and type alias it to IterableDynamicNodeWrapper in jvm.