RFR: JDK-8210918, Add test to exercise server-side client hello processing

[Jamil Nimeh]

Hello all,

This adds a test that lets us send different kinds of client hellos to a 
JSSE server. It can be extended to handle different kinds of corner 
cases for client hello extension sets as well as fuzzing test cases in 
the future.  It also provides some extra test coverage for JDK-8210334 
and JDK-8209916.

Webrev: http://cr.openjdk.java.net/~jnimeh/reviews/8210918/webrev.01/
JBS: https://bugs.openjdk.java.net/browse/JDK-8210918

Thanks and have a good weekend,
--Jamil