Code Review Request: TLS 1.3 full handshake (JDK-8196584)

[Anthony Scarpino]

I found some commented out code that I will remove in 
CertificateMessage, lines 1300-1319 on my next push unless this should 
be uncommented.

In SupportedVersionsExtension.java, HRRSupportedVersionsProducer and 
HRRSupportedVersionReproducer could be merged with a boolean in the 
constructor to define it as a producer or reproducer.  The only 
difference right now between the classes is whether to put 
HRR_SUPPORTED_VERSIONS in the handshakeExtension.  But it is minor is ok 
as is.

Most of the files I've gone through are small nits and spelling that I 
will update.

Tony