RFR: 8193892: Impact of noncloneable MessageDigest implementation

[Seán Coffey]

Looking to push a new test which helps test CloneableDigest code. It's 
something that arose during JDK-8193683 fix.

The test was contributed by Brad Wetmore. I've converted it to use the 
SSLSocketTemplate.

JBS : https://bugs.openjdk.java.net/browse/JDK-8193892
webrev : http://cr.openjdk.java.net/~coffeys/webrev.8193892/webrev/

-- 
Regards,
Sean.