[Nestmates] RFR: 8189158: [Nestmates] Expand test coverage

[David Holmes]

webrev: http://cr.openjdk.java.net/~dholmes/8189158/webrev/

Reflection tests need to be run in such a way to check both the native 
accessors and the generated accessors.

Reflection should check static class and o.getClass

TestInvokeHierarchy needs a reflection and MethodHandles version.

Thanks,
David