RFR 8183938: [MVT] Add test for mock vector API

[Maurizio Cimadamore]

Hi,
this changeset adds the mock vector API test that Vlad has worked on. I 
cleaned it up a bit and converted to a working testng test.

http://cr.openjdk.java.net/~mcimadamore/8183938/

Cheers
Maurizio